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M2 Series

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1. 40 41 Roll Out Limit Control 41 Draft Inducer Motor 41 42 Pressure 42 44 Hot Surface oe oer eee o d aaa 44 Gas Valve 44 46 Flame uuu 46 Heat Exchanger and 15 Components 46 47 Blower Performance 46 47 Flue Gas Temperature 47 Natural Gas Pipe amp LP Gas Pipe Capacity Table 47 INTRODUCTION This service manual is designed to be used in conjunction with the installation manual provided with each furnace Thiscondensing furnace represents the very latest in high efficiency gas furnace technology Consequently certain controls within the furnace consist of highly sophisticated electronic components which are not user serviceable Therefore it is essential that only competent qualified service personnel attempt to install service or maintain this product This service manual was written to assist the professional HVAC service technician to quickly and accurately diagnose and repair any malfunctions of this product This service manual covers both upflow models and downflow models installed as direct vent model non direct Vent applications The overall operation of all these models is basically
2. screws minimum on each duct flap An alternate attachment method is acceptable as long as the plenum is securely attached 6 Tape the duct flap edges with an approved tape for a leak free joint INSTALL DOWNFLOW FURNACE a Prepare the A C coil box as described in the instructions provided with the coil box b Place A C coil box onto duct connector c Slide A C coil box back until it is firmly against the mounting plate Mounting plate tabs should be bent upwards so as not to interfere with furnace d Secure front with one 1 fastener at each corner through front bottom flange and through the back of the A C coil box e Position the furnace on top of the A C coil box Ensure thatthe furnace is properly positioned on the wrapper f Secure the A C coil box to the bottom of the furnace The A C coil box can be secured to the furnace using the provided attachment brackets These brackets are designed to attach the furnace cabinet to the A C coil box on the sides To install these brackets position one bracket on the side of the furnace so that the locating dimples are in the groove created by the bottom of the furnace cabinet and the top of the A C coil box Using the provided self drilling screws secure the bracket to the A C coil box and to the furnace Repeat on the other side of the furnace for the other bracket NOTE Additional fasteners may be used at rear sides or through door frame as desired to secure furnace
3. e AIR CONDITIONER CONDENSING UNIT BLACK FLAME SENSOR 3 OR 4 SPEED MOTOR Field Wiring Factory Wiring Low Voltage High Voltage STATUS RED FAULT CONDITION THESE WIRES Power On NOT PRESENT I am ON 3 SPEED Limit Circuit Open or External Load On W 1 FLASH MODELS Pressure Switch Stuck Open 2 FLASHES Pressure Switch Stuck Closed 3 FLASHES Ignition Failure Check Ground 4 FLASHES 115 amp Neutral Reversed or no Ground 5 FLASHES False Flame or Gas Valve Relay Shorted Continuous If any of the original wire as supplied r Q with the furnace must replaced it must replaced with wiring material having atemperature rating of atleast YELLOW FAULT CONDITION LIGHT 105 C Use copper conductors only Power Otf Low Flame Sensor Signal Continuous Flash Flame Present Figure 33 Furnace Wiring Diagram 37 Polarity may verified as follows Turn power supply Using a Voltmeter check for voltage between the Hot Black and Neutral White wire of supply circuit Reading should be Line Supply Voltage Check for Voltage between the Neutral White wire and Ground wire of the supply circuit Reading should be zero Voits if line voltage is read polarity is reversed zero Volt reading indicates there is no voltage potential on Neutral wire Double check by checking
4. 5 Turn OFF the electrical power to the appliance To Remove the Burner Assembly 1 Follow the instructions To Turn Off the Fuel Supply to the Appliance 2 Disconnect the flame sensor wire from the burner box 3 Disconnect the ignitor wires at the 2 pin plug This is a locking quick connect and both sides of the lower section must be depressed in order to be separated 4 Remove the wires from the terminals of the gas valve 5 Disconnect the rubber pressure tubes from the gas valve and the burner box 6 Removethe burner access cover plate from the burner box Hemove supply gas piping from the gas valve 8 Carefully remove the burner assembly fasteners and removethe burner assembly fromthe appliance Keepthe fastenersthatwere removed Note thatthe burner box may have hooks near the top and on the right and left hand sides Toremove this type of burner box liftthe burner box upwards and then remove the box from the unit N To Remove the Burner Orifices 1 Remove the four 4 fasteners that secure the gas manifold to the burner box as shown in Figure 23 Carefully remove the gas manifold assembly from the burner box Note that the gas manifold assembly consists of the gas valve the gas manifold and the orifices 2 Carefully remove the burner orifices from the gas manifold as shown in Figure 23 Elevation 8000 10000 LP Nat LP Nat LP Nat sooo 4 t s as f s ps se a 56 57 x 57
5. Fan Mode 1 Onacall for fan operation the thermostat applies 24 VAC to the G terminal on the furnace control board 2 The circulating air blower is energized immediately on the heating speed 3 Ifthe furnace is operated in the continuous ON position at the thermostat and is then switched to AUTO the circulating blower will operate for a specified delay factory set at 120 seconds Furnace Fails to Operate If the furnace does not operate check the following 1 15 thermostat operating properly 32 Are the blower compartment door s in place Is the furnace disconnect closed Has the circuit breaker tripped or the control board fuse burned open Is the gas turned on Are any manual reset switches open Is the filter dirty or plugged Is the flame sensor coated Remove and clean with emery cloth P ON If the furnace locks out after 5 attempts for ignition it will try again every hour if acall for heat remains If the inducer and circulating air blowers are operating and items 1 through 8 have been checked press the red reset button on the vent safety switch See Figures 30 amp 31 If the furnace operates after depressing the reset button contact a qualified service technician to identify and repair the problem If furnace continues to not operate depress the red reset buttons on the flame roll out switch If the furnace operates after depressing the reset button contact a qualif
6. To avoid electric shock personal injury or death turn off the power at the disconnect or the main service panel before making any electrical connections ELECTRICAL WIRING General Electrical connections must be made in accordance with all applicable local codes and ordinances and with the current revision of the National Electric Code ANSI NFPA 70 Line Voltage Wiring The line voltage 115 volt to the furnace must be supplied from a dedicated branch circuit containing the correct fuse or circuit breaker for the furnace See Table 9 An electrical switch should be readily accessible from and within sight of thefurnace Seethe Wiring Diagram labelin the furnace for more details Thefurnace cabinet must have an uninterrupted unbroken ground to minimize injury shouldan electrical fault condition occur The controls used in this furnace require an earth ground to operate properly Acceptable methods for grounding are electrical wire or conduit approved for electrical ground service Do not use gas piping as an electrical ground NOTE Proper line voltage polarity must be maintained in order for the control system to operate correctly Verify that the incoming neutral line is connected to the white wire and the incoming hot line is connected to the black wire in the furnace junction box The furnace will not operate unless polarity and ground are properly connected See Figure 26 Furnace Cabinet Nominal Maximum Input Width
7. Furnace Airflow Data Furnace Furnace Input Motor Model No Btuh Speed Med High M2RC 080 80 000 Med Low Low High Med High M2RC 100 100 000 Ow Low High Med High M2RL 080 80 000 Med Low Low High Med High M2RL 100 100 000 Meqi ow Low Factory wired cooling speed tap Factory wired heating speed tap NOTE Data is for operation with filter External Static Pressure Inches Water Column Not Recommended Table 2 Furnace Airflow Data AIR DISTRIBUTION SYSTEMS For proper air distribution the supply duct system must be designed so that the static pressure measured external to the furnace does not exceed the listed static pressure rating shown on the furnace rating plate Threetypical distribution systems are illustrated in Figure 3 Location size and number of registers should be selected onthe basis of best air distribution and floor plan ofthe home A Single trunk duct x B Dual trunk duct w crossover connector Transition duct w branches Figure 3 Typical Supply Duct System UPFLOW FURNACE INSTALLATION a Positionthefurnace ontop ofthe return air ductwork or return air stand 10 NOTE The ductwork or stand must have an opening equal to that of the return air opening of the furnace Refer to Figures 1 amp 2 forthe proper return air opening size Secure the furnace to the floor or base once ithas been properly positioned b Position and secure the
8. at intervals nogreaterthan fivefeet and atsmaller intervals if necessary to ensure that there are no sagging sections to trap water See Figures 15 amp 16 Figure 17 illustrates vent and combustion air pipe sizes exiting the furnace Transition to the correct pipe size must be done close to the furnace so that the full length of pipe is of proper size Thesecondensingfurnaces have beencertifiedfor installation with zero clearance between vent piping and combustible surfaces However it is good practice to allow space for convenience in installation and service Pipe Couplings at the Furnace The provided rubber couplings should be installed in the combustion air 3 diameter and vent 2 diameter pipes to allow for servicing These couplings are designed to fit snugly over the pipe and be secured to the pipes using the provided hose clamps Refer to figures 15 and 16 for the proper installation of these couplings 17 Location of Outdoor Terminations Vent and combustion air intake terminations must be located to ensure proper furnace operation and to conform to applicable codes Figure 14 illustrates necessary distances from the vent termination to windows and building air intakes In Canada the Canadian Fuel Gas Code takes precedence over these instructions Specifically all minimum distance requirements with respect to termination of the vent piping listed below The following list is a summary of vent terminal locati
9. 811 1 606 1 496 The Example LP Input Btu requirement of unit 150 000 Equivalent length of pipe 60 ft 3 4 IPS required 983 1000 Replaces 983A 0200 Specifications andillustrations subjectto change without notice and withoutincurring obligations St Louis MO NORDYNE Printed in U S A 10 00
10. A C coil box to the top of the furnace The A C coil box canbe secured to the furnace using the provided attachment brackets These brackets are designed to attach the furnace cabinet to the A C coil box on the sides To install these brackets position one bracket on the side of the furnace so that the locating dimples are in the groove created by the top of the furnace cabinet and the bottom of the A C coil box Using the provided self drilling screws secure the bracket to the A C coil box and the furnace Repeat on the other side of the furnace for the other bracket c Attach the plenum from the supply duct to the flanges of the A C coil box d Secure the plenum to the supply ductwork NOTE Additional fasteners may be used at rear sides or through door frame as desired to secure furnace to closet or alcove framing DOWNFLOW FURNACE INSTALLATION DUCT CONNECTORSELECTION FOR DOWNFLOW MODELS a Determine depth of floor cavity from surface of floor to top of supply air duct See Figure 4 b Select appropriate model from Table which matches X dimension ofthe floor cavity To maximize air delivery remove reducer C see Figure 6 to obtain the largest open area that will fit the duct floor construction INSTALLATION OF THEDUCT CONNECTOR FOR dr DOWNFLOW INSTALLATIONS 6 depth equal to X in Figure 6 and Table 3 Required cut out openings in the floor ceiling roof and or walls must be carefully located to av
11. Auto reset after one hour Reverse Polarity Unit does not operate Reestablish Ground Main Power or Both fans operate Thermostat resets Table 11 Status Light Conditions 1 Red Status Light An explanation of the flash code may be seen on the inside of the door Note The light must be observed before the bottom door is removed since the board does not store the fault condition in its memory See Table 11 2 Yellow Flame Light This will come on solid with a flame signal of 1uA or more The flame light will blink at the point of a weak signal and go out at any reading of 5 uA or less See Flame Sensor section on page 43 High Limit Controls The M2R L series incorporates 3 different types of limit controls See Figure 42 a main limit control which is located inthe heat exchanger front panel a vent limit control located on the inducer housing and 1 roll out switch on the burner box cover plate Alllimits are in series with each other and are between 3 and 8 pins on the nine pin connector that plugs into the control board Limit controls are normally closed switches that open thermostatically to prevent furnace operation in unsafe temperature conditions 40 Manual Heset Figure 42 Main Air Limit Control See Figure 43 The main limit control is an automatic reset type It reacts to abnormally high air temperatures in the heat exchanger area If the main limit opens the gas valve is de ene
12. Connector Ground Ground Ground Field Line Voltage Wiring Factory Line Voltage Wiring Ground Field Supplied Disconnect Within Sight of Furnace Figure 26 Line Voltage Field Wiring 27 The thermostat must not be installed an outside wall or any other location where its operation may be adversely affected Adverse affects include radiant loading from fireplaces sunlight or lighting fixtures and convective loading from warm air registers or electrical appliances To check the heat anticipator setting either 1 Addthe current draw of the system components or 2 Measurethe current flow on the thermostat R W circuit after the circulating blower motor has started Set the heat anticipator according to the thermostat manufacturer s instructions for heat anticipator settings Connect R amp W For Heating Only Hoom Thermostat NOTE The Y terminal on the UTEC control board must be connected to the thermostat FIELD WIRING Low Voltage Connections u gt L C VENTILATION Adequate ventilation must be provided for the home This ventilation can be supplied by the VentilAire or VentilAire IV accessories Alternate means to provide the ventilation air must meet the requirements of all applicable local and federal codes For downflow models a bracketis supplied with the furnaces to allow the use of the VentilAire or VentilAire IV acc
13. Hard Tube In Line Drain Assembly Burner Box Assembly Header Outlet Box Cased Coil Wrapper Filter 18 x 20 x 1 Not Shown VentilAire Bracket Attachment Bracket Turbulator Not Shown Auxiliary Limit Switch 120 Not Shown Inducer Orifice Not Shown Inshot Burner Not Shown Natural and LP Gas Orifice Not Shown Ignitor Not Shown Heat Exchanger Assembly Not Shown Capacitor Assembly 10 MFD 370V Not Shown Blower Wheel CCW Not Shown Motor 1 2 HP Not Shown Access Door Not Shown Figure 31 M2RL Location of Major Components Troubleshooting Flow Chart Use in conjunction with time sequence and wiring diagram that follows Call for heat Yes t stat closes R W No 24 Volt C to WJ No Check for red light No Check fuse on circuit board on circuit board on circuit board Yes replace if no continuity Is light blinking 5 times Polarity is reversed Switch L1 amp L2 Note Retry Will retry 4 more times Burners stay on Every Soft lock out blinks 4 times Hour on status light Power down and back up to reset longer than 6 seconds Yes Main blower starts after No delay time 30 seconds Inducer starts NO gt Check for voltage No X Circuit board 3 blinks at inducer molex plug Yes Y Yes es Replace Inducer Replace Pressure switch Blower Board stuck closed Pressure switch No Gircuitb rd cl
14. Kit Order Number Fossil Fuel Kit 914762 A C Coil Box 914958 914098 914229 917201 903578 902373 902375 902377 Table 5 Accessory Kits Sloped Roof VentilAire Kit Sloped Roof VentilAire IV Kit Soffit VentilAire Kit Concentric Vent Termination Kit for horizontal and vertical ventino Horizontal Exterior Vent Mounting Kit 2 PVC 3 PVC Neutralizer Kit All Models Concentric Vent Termination A concentric vent termination is approved for use with these furnaces The kit part number is listed in Table 5 For proper installation of the concentric vent termination follow the installation instructions provided with that kit DRAINAGE OF CONDENSATE FROM FURNACE NOTE The condensate drain should be protected from freezing when in unheated spaces The condensate drainage system is internal to the furnace The drain may exit either the left or right side of the furnace cabinet For a right side drain simply extend the tubing out of the 7 8 hole in the cabinet See Figure 21 For a left side drain follow the steps below 1 Loosenthe clamp on the soft exit tube see Figure 21 2 Hotatethe softexittube counter clockwise 180 upflow models clockwise 90 downflow models 3 Re tighten the clamp MAKE SURE CLAMP IS TIGHT TO AVOID LEAKAGE OF CONDENSATE 4 Route the tubing out of the 7 8 hole located 8 inches up from the bottom furnace A Collector Box Rotate clockwise a x Route to vy M fl
15. Table 7 Approximate Orifice Size for Natural and LP Gases 24 Orifices Manifold Flame __ Observation E Burner Box Figure 23 Typical Installation For Sealed Burner Box With Access Cover Plate N CAUTION Caution Do not re drill the burner orifices If the orifice size mustbe changed use only new orifices Note The size of the new orifices that will be installed into the unit will depend upon the type of conversion sea level or high altitude natural gas or LP gas To Convert the Unit to the Alternate Gas 1 2 Remove the orifice bag from the manifold of the unit Install the appropriate gas burner orifices into the gas manifold Remember if installing in the United States at altitudes above 2 000 feet to install the proper orifices shown in Table 7 When installing the new orifices DO EXAMPLE 1 3 890 feet Natural M2RC100A 16 BN 45 Drill Elevation Type of gas Furnace model Orifice as shipped What burner orifices are needed The required input for 3890 feet is 84 000 Btuh or 16 less than the sea level rating of 100 000 Btuh See Table 7 for natural gas find the Furnace Model Number and follow across the table for the elevation 2000 4000 column From the table choose a 46 orifice Install a 46 orifice in every burner and checkthe firing rate perthe VERIFYING AND ADJUSTING FIRING RATE section The firing rate in this example must not exce
16. as Kanthal D Figure 59 Check out Procedure 1 Use micro amp meter or the micro amp setting on a digital volt ohmmeter to measure the flame current signal uA scale Disconnect flame sensor at the push on connector below the burner assembly Put meter probes series with flame sensor connectors Establish a call for heat After flame is established note micro amp reading A strong signal is 3 to 4 uA See Figure 60 The board will close the gas valve if the micro amp reading is less than 0 5 uA N Ol 46 Figure 60 7 To aid in troubleshooting the ignition control has a yellow flame signal light If the light is on flame signal is at 1 or higher micro amps Ifthe light is blinking signal is below 1 uA and is weak Reasons for Poor Micro Amp Readings See Figure 61 Dirty flame sensor Poor positioning of flame sensor Poor ground on furnace Low gas pressure High gas pressure Studies have shown that silicone oxides may accumulate on the sensor It is important that the furnace operates in an environment which is conducive to proper furnace operation These oxides can be removed by brushing with steel wool puc Figure 61 Heat Exchanger and Its Components See Figure 62 TheM2usesatubulartype of primary heat exchanger made from aluminized steel and stainless steel secondary Inside the heat exchanger are the tubulators located behind the collector box Figure 62
17. during any of the above tests the venting system must be corrected Proc der comme suit pour chaque appareil raccord la tuyauterie d vacuation eten tat normal de fonctionnement tous les autres appareils raccord s la m me tuyauterie d vacuation doivent tre mis hors service a sceller toute ouverture non utilis e de la tuyauterie d vacuation b s assurer que la tuyauterie d vacuation pr sente des dimensions et une pente horizontale conformes la norme ANSI Z223 1 intitul e National Fuel Gas Code ou aux codes d installation CAN CGA B149 ainsi qu aux pr sentes instructions S assurer que la tuyauterie n est pas bloqu e restreinte corrod e qu elle ne fuit pas et qu elle ne pr sente aucun autre d faut potentiellement dangereux c danslamesure du possible fermertoutes les portes et fen tres du b timent ettoutes les portes entre la pi ce se trouve l appareil raccord la tuyauterie d vacuation et les autres pi ces du b timent Mettre en service les s ccheuses et tout autre appareil qui n est pas raccord la tuyauterie d vacuation Faire fonctionner r gime maximal tout ventilateur d vacuation tel que les hottes de cuisini re et les ventilateurs de salles de bains Ne pas mettre en service les ventilateurs d t Fermer les registres des foyers d respecter les instructions d allumage Mettre en service l appareil l essai R gler le thermostat de mani re ce que l app
18. inside each tube See Figure 63 They help in the efficiency of the combustion process BLOWER PERFORMANCE Proper Airflow Checking Temperature Rise See Table 2 page 7 Atemperature rise may be taken across the furnace by checking the temperature of the supply duct and subtracting the return air temperature lf the temperature rise is too high air flow must be increased by increasing blower speed or removing any restriction to airflow If temperature rise is too low air flow is too great Reduce air flow by using a low speed on the blower Causes for excessive temperature rise 1 Dirty air filter 2 Oversizedfurnace undersized duct Blower speed too low 4 Dirty evaporator coil 5 Overfired furnace due to too much gas pressure FLUE GAS TEMPERATURE The M2 series furnaces flue gas temperature range is between 100 F and 130 F Make a small hole in vent pipe as close to furnace as possible Insert temperature probe andnote temperature Possible causes for high flue gas temperatures 1 Dirty secondary heat exchanger 2 much gas pressure 3 Not enough air flow across furnace Low flue gas temperatures may be attributed to 1 Too little gas pressure 2 Too much air flow 3 Verylowreturn air temperature After flue gas has been measured reseal vent pipe Figure 63 Natural Gas Pipe Capacity Table CU FT HR Capacity of gas pipe different diameters and lengths in cu ft per hr wit
19. position 5 Turn OFF the electrical power to the appliance Verifying and Adjusting Firing Rate The firing rate must be verified for each installation to prevent over firing the furnace NOTE The firing rate must not exceed the rate shown on the furnace rating plate At altitudes above 2000 ft it must not exceed that on the rating plate less 4 for each 1000 ft Use the following procedure to determine the firing rate 1 Shut off all other gas fired appliances 2 Start the furnace and allow it to run for at least three minutes 3 Measure the time in seconds required for the gas meter to complete one revolution 4 Convert the time per revolution to cubic feet of gas per hour using Table 10 5 Multiply the gas flow rate in cubic feet per hour by the heating value of the gas in Btu per cubic foot to obtain the firing rate in Btuh Example Time for 1 revolution of agas meter with 1 cubic foot dial 40 seconds From Table 10 read 90 cubic feet per hour of gas e Heating value ofthe gas obtained from gas supplier 1040 Btu per cubic foot Firing rate 1040 x 90 93 600 Btuh 6 Relatively small adjustments to the firing rate can be made by adjusting the gas manifold pressure 7 See the High Altitude Derate section for additional information on firing rate at elevations above 2000 ft The gas valve regulator is set at a nominal value of 3 5 in water column for use with natural gas The manifold pressu
20. 4 10 18 1 4 174 100C 100 000 19 3 4 18 1 4 10 18 1 4 185 m p Return Air Opening 1 4 w 27 7 8 19 3 4 cn Fi T 2 1 2 Bottom Supply Air Opening Side 6 1 4 lt 18 1 4 Bottom Supply Air Opening 24 7 8 Combustion Air Inlet 7 8 Dia Electric Connection 1 1 2 x 2 1 2 Knockout For Gas Connection 21 1 2 lt 21 7 8 19 3 4 _ gt Condensate Drain Outlet 20 lt 20 3 4 penunuo SNOISN3OMNIG LINN MODEL IDENTIFICATION CODE M 2 RC Application M Manufactured Home Furnace Series Comfort Model RC Condensing Upflow Condensing Downflow NWARNING Products of combustion must not be allowed to enter the return air openings of the furnace or the circulating air supply Failure to prevent products of combustion from being circulated into the living spacecancreate potentially hazardous conditions including carbon monoxide poisoning that could result in personal injury or death The floor or platform on which the furnace is mounted must provide sound physical support of the furnace with no gaps cracks or sagging between the furnace and the floor or platform Thecirculatingair ductwork mustnot be connected to any other heat producing device such as a fireplace insert stove etc CIRCULATING AIR SUPPLY General Plenums and air ducts must be installed in accordance with the S
21. 4 times repetitively The thermostat must be opened for at least ten seconds to reset the furnace control after a lock out Otherwise the furnace will attempt another ignition sequence in 1 hour 8 Thefurnace control energizes the circulating air blower on the heating speed 30 seconds after the gas valve circuit is energized 9 When the thermostat has been satisfied gas valve is de energized 10 Theinduceris de energized after a 30 second postpurge 11 The furnace control keeps the circulating air blower energizedfor 120 seconds factory set or 60 90 or 180 seconds field adjustable See Figure 28 12 Abnormal conditions If a limit opens during operation the inducer and circulating air blower continue to operate The gas valve is de energized immediately The blowers continue to operate until the limit closes When the limit closes the inducer blower is de energized immediately The circulating air blower continues to operate for the specified delay factory set at 120 seconds Cooling Mode 1 Onacallfor cooling the thermostat closes applying 24 VAC to the G and Y terminals on the furnace control This closes the compressor contactor 2 The furnace control energizes the circulating blower 115 VAC on the cooling speed 3 Whenthe thermostatis satisfied the G and Y terminals on the control board are de energized opening the compressor contactor 4 The circulating air blower is de energized after a 90 second delay
22. 51 psig and must not be less than 11 0 in W C 0 40 psig 4 Theroll out and vent safety manual reset switches are closed If necessary press the red button to reset a switch See Figure 32 for location DO NOT install a jumper wire across a switch to defeat its function If a switch reopens on start up DO NOT reset the switch without identifying and correcting the fault condition which caused the switch to trip 5 Theblower door isin place closing the door switch in the line voltage circuit 6 The gas line has been purged and all connections are leak tight Start Up Procedure 1 Setthe thermostat to the lowest setting 2 Close the disconnect s to provide line voltage to the furnace 3 Follow the procedures given on the operating instructions label attached to the furnace 4 Setthe thermostat above room temperature and verify the sequence of operation See the SEQUENCE OF OPERATION 5 After the furnace has run for approximately five minutes set the thermostat below room temperature and verify steps 9 11 of the SEQUENCE OF OPERATION Shut Down Procedure In the event that the furnace must be shut down follow this procedure 1 Set the room thermostat to OFF or its lowest temperature setting 2 Turn OFF the main gas supply to the appliance at the manual valve outside of the appliance casing 3 Remove the control access panel louvered door 4 Move the appliance gas valve lever knob to the OFF
23. C for natural gas and8 5 WC for LP gas without changing the orifices 45 for Natural Gas 55 for LP Gas NOTE The density of air decreases with increasing elevation above sea level This reduces the quantity of combustion air drawn into the furnace under normal operation and requires the unit be derated by using smaller CONVERSION This furnace can be converted from the factory equipped gas to either natural gas for LP gas ready models or LP gas for natural gas ready models Conversions must be made by qualified service personnel using only factory authorized or approved parts The required conversion orifices are supplied with the furnace Furnace Furnace Rating No of Model Number Plate Input Burners M2R C L Btuh Nat LP 080A 16 B 100 16 N or L 1 00 000 Elevation Elevation Elevation Elevation 0 T 2000 us 4000 E 6000 8000 LP NWARNING DO NOT REMOVE OR DEFACE THE ORIGINAL RATING PLATE N CAUTION The gas supply shall be shut off prior to disconnecting the electrical power before proceeding with the conversion To Turn Off Fuel Supply to the Appliance 1 Set the room thermostat to OFF or its lowest temperature setting 2 Turn OFF the main gas supply to the appliance at the manual valve outside of the appliance casing 3 Remove the control access panel louvered door 4 Move the appliance gas valve lever knob to the OFF position
24. Electrical Operating Btuh in Supply Voltage 80 000 100 000 Thermostat Wire Gauge 24 22 20 18 Time Delay Fuses or HACH type circuit breakers are required N CAUTION Label all wires prior to disconnection when servicing controls Wiring errors can cause improper and dangerous operation Verify proper operation after servicing N ATTENTION Lors des op rations d entretien des commandes tiqueter tous les files avant des les d connecter Toute erreur de c blage peut tre une source de danger et de panne S assurer du bon fonctionnement de l appareil apres tout entretien Low Voltage Wiring Install the thermostat per the manufacturer s instructions The low voltage 24 volt connections from the thermostat are made at the terminal strip on the control board in the furnace See Figure 27 for the proper connections for heating only two wire and heating cooling four wire applications The recommended minimum wire gauge for thermostat wiring is shown in Table 9 Maximum Fuse or Circuit Breaker Amps Minimum Maximum Minimum Operating Furnace Wire Voltage Amperes Gauge 19 75 115 60 1 127 103 14 1 14 15 19 75 115 60 1 127 103 14 1 14 15 Recommended Thermostat Wire Length 4 or 5 wire cooling 2 wire heating 55 ft 25 ft 90 ft 45 ft 140 ft 70 ft 225 ft 110 ft Table 9 Electrical Data Field Supplied Fused Service Panel P Black Hot eae Field Supplied Panel
25. M2 Series 90 High Efficiency Upflow Downflow Models Service Manual Typical meters used to service furnaces Differential Pressure Gauge Volt Ohm Meter Manometer Slant Gauge TABLE OF CONTENTS Page IntrOdUcllOl uu uuu u l u meiste age 5 9 eni 6 Clearances To Combustible Materials 6 Unit DIMENSIONS 7 8 Model Identification Code 9 Circulating Air Supply 9 10 erra 9 Return Air Provisions 9 Airflow Data 10 Air Distribution Systems 10 Upflow Furnace Installation 10 Downflow Furnace Installation 10 15 Duct Connector Selection For Downflow t 10 Installation Of The Duct Connector Downflow Installations 11 Cut Out Floor Opening For Downflow uzun 11 12 Qut Duct Opening usu Dua ua ata 11 Install Furnace Mounting Plate 11 13 Install Duct Connector 11 14 Alternate Attachment Methods 14 15 Install Downflow Furnace 15 Venting and Combustion Air Requirements 15 General u u w m a um
26. M2RC un Ibs 080C 100C ids PN Bd M 1 2 n pm gt pp lt 19 1 2 y gt aia lt lt 18 1 4 lt 203 4 id Cover A C Coil Box Plate 20 Combustion Air 20 k Inlet Combustion gt 14 m Air Inlet 27 5 8 Exhaust Vent lt 22 1 2 gt lt lt 25 1 8 2 1 4 1 1 2 x 3 1 2 Dia 1 1 2 x 3 1 2 Dia Opening for Opening for Gas Connection _ Gas Connection 7 8 Dia Electric ee 43 25 1 4 gt 33 lt lt 2558 30 1 4 25 1 4 20 1 2 di Bott Ret ottom Return p Am lt Opening Y lt 17 gt Bottom Return Opening 19 3 4 2 1 4 lt 28 Drain Outlet SNOISNAWIG suoisuauiiq HUN TAZIN Z Downflow Furnace Combustion Air Inlet lt 24 1 2 gt Exhaust Vent lt lt 3 4 4 Exhaust Vent 2 lt 1 9 3 4 gt 24 7 8 7 8 Dia Electric lt lt 21 7 8 11 2 x 3 1 2 0 Opening for Gas Connection 21 1 2 15 1 2 lt lt 21 1 4 gt M Condensate Drain Outlet A C Coil Box lt 20 3 4 amp 19 3 4 Bottom Supply Air Opening 3 4 Model Dimensions inches Shipping Number Btuh Weight M2RL A B C D Ibs 080 80 000 19 3 4 18 1
27. Number and follow across the table for the elevation 4000 6000 column From the table choose a 56 orifice Install a 56 orifice in every burner and adjust the manifold pressure to 10 0 inches water column The firing rate in this example must not exceed 76 000 Btuh Reconnect the gas piping to the gas valve the wires to the gas valve terminals the rubber pressure tubes to the gas valve and the burner box Reinstall the burner access cover plate 6 Reconnect ignitor at the 2 position plug 7 Reconnect the flame sensor wire to the burner box CIE Pressure Gauge Installation NOTE For natural gas installations the incoming gas line pressure at the gas valve inlet must be between 4 5 WC and 10 0 WC For LP gas installations the incoming gas line pressure at the gas valve inlet must be between 11 0 WC and 14 0 WC This pressure can be checked at the inlet end of the gas valve using a pressure gauge or U tube manom eter which mustbe installed according to the manufacturer s supplied instructions Lighting and Adjustment of the Appliance 1 TurnONthegas atthe manual valve outside of the unit 2 Check all gas connections for leaks with a soap and water solution If the solution bubbles there is a gas leak which must be corrected Do NOT use an open flame to check for gas leaks Turn ON the electrical power to the appliance Move the gas valve lever knob to the ON position Th
28. The off times are field adjustable and may be set from 180 120 90 69 seconds 120 being set from the factory To change the off time remove jumper pin and replace it on the desired time Time on is fixed at 30 seconds See Figure 39 Lam Figure 39 D Humidifier amp Electronic Cleaner Tap Both taps are rated at 1 amp and have an output voltage of 120 VAC All humidifiers and electronic air cleaners should be installed perthe installation instructions the manufacturer supplied with their equipment See Figure 40 Note A 24 volt humidifier solenoid coil must not be wired across the W and C terminal This will interfere with the operation of the control board and may influence the heat anticipator thermostat Figure 40 F Diagnostic Lights the diagnostic light feature is to aid the service technician in identifying the nature of the problem See Figure 41 Figure 41 39 Main Blower amp Induced Draft Condition Flashes No Fault LED on Limit Circuit open 1 Pressure Switch 2 stuck open Pressure Switch stuck closed Ignition Failure Unit will try 5 times 4 for ignition Polarity or Ground 5 False Gas Valve Shorted Power LED Status of Fault Furnace Clearing Normal G C Limit Circuit closes Motor running Induced Draft Motor running Pressure Switch closes Pressure Switch Unit does not operate opens Unit does not operate
29. a Q 15 Venting Requirements 15 22 General Jaya uya ya yaa 15 17 Vent Pipe Material 17 Vent Pipe Length and Diameter 17 Vent Pipe Installation 17 22 Pipe Routing and Support 17 20 Pipe Couplings at the Furnace 17 20 Location of Outdoor Terminations 18 21 Horizontal Venting 21 22 Vertical Venting 21 22 Vent Freezing Protection 22 Concentric Vent Termination 22 Drainage Of Condensate From Furnace 22 23 Gas Supply And Piping 23 24 General amas 23 24 24 High Altitude Derate 24 ConVerslolnl 24 26 Pressure Gauge Installation 26 Lighting And Adjustment Of The Appliance 26 Adjusting The Manifold Pressure 26 Page Conversion continued Completing The Conversion 26 Electrical Wiring 26 28 General 27 Line Voltage Wiring 27 Low Voltage Wiring 2 28 Ms 28 29 Start Up And Adjustme
30. adaptor for connection to furnace 20 Support System on Vertical Rise Below Joints N ml Support System with first support as close to the furnace as possible Exhaust Vent Upward Pitch m 1 4 per foot Rubber Coupling w 2 Clamps Coil Box C Furnace Furnace Front Support System on Vertical Rise Below Joints N as close to the furnace as possible i Support System with first support Combustion Air Pipe Rubber Coupling w 2 Clamps Upward Pitch 1 4 per Foot lt Furnace Figure 16 Vertical Venting Downflow Furnace Combustion Air Inlet 3 PVC on 080 100 models Furnace Top Combustion Air Inlet Pipe Collar Diameter 3 for coupling or reducer Furnace Top 2 PVC 2 PVC Exhaust Vent Exhaust Vent Models Models Use appropriate adaptor for connection to furnace Figure 17 Furnace Pipe Adaptions Vent Configuration to Provide 12 Minimum height above Snow Level Outside gt Wall 12 Above Normally Expected Snow Level Pipe Couplin pang Armaflex Insulation Equivalent Figure 18 Alternate Horizontal Vent Installation Horizontal Venting Vent and combustion air intake terminations must be as shown in Figure 19 WARNING Ensure thatthe combustion air ventand the exhaust vent are configured as shown Figure 19 Improper vent te
31. al reasons why Crack or hole in heat exchanger Vent blockage Heat exchanger blockage Poor seal on collector box to induced draft motor Bad blower wheel in induced draft motor UI s Iu Figure 52 The switch must be open to be ready for the next heating cycle switch remains closed a flash code of 3 will be produced by the control board 43 Lower lesser Differential Negative Pressure Than Closing Pressure Lower than normal negative pressure measured at the combustion blower may be caused by 1 Restriction on outlet side of combustion blower blocked flue debris or water building up in flue piping not properly supported or sloped Leak lack of restriction on inlet side Inducer inlet leaking inducer blower wheel loose leak in heat exchanger or wrong restrictor orifice The most common occurrence is improper or slow condensate removal or dry tap To test for restriction in outlet pipe exhaust to verify problem is outside of furnace disconnect exhaust for test period only and start furnace furnace starts look for problem in vent pipe Reconnect after testing Higher than normal negative pressure at burner box acts to open switch 1 Restricted combustion air inlet pipe may be blocked too long too small or have too many elbows To verify if problem is in inlet pipe disconnect pressure switch hose at burner box and start furnace If furnace starts look for problems mentio
32. areil fonctionne sans interruption DIRECT VENT DUAL PIPE LENGTH ft with two long radius elbows one on each pipe Inlet Outlet 3 3 APPLICATION or ABS SCH 40 Pipe Size Models M2RC M2RL 080 Models M2RC M2RL 100 NOTES Subtract 3 5 ft for each additional 3 elbow Two 45 degree elbows are equivalent to one 90 degree elbow One short radius elbow is equivalent to two long radius elbows Do not include termination elbows in calculation of vent length This table is applicable for elevations from sea level to 2000 ft For higher elevations decrease vent pipe lengths by 8 per 1000 ft of altitude Only the above pipe materials are approved for use with these condensing furnaces Table 4 Vent Table 16 e S assurer qu un appareil d un coupe tirage pr sente aucune fuite l ouverture du coupe tirage apr s que le br leur principal ait fonctionn pendant cinq minutes Employer la flamme d une allumette ou d une chandelle f Apr s avoir d termin que tous les appareils raccord s la tuyauterie d vacuation vacuent correctment tel que prescrit ci dessus rouvrirles portes etles fen tres et remettre les ventilateurs d vacuation les registres de foyers et tout autre appareil fonctionnant au gaz aleur tat de fonctionnement initial g Siunappareil n vacue pas correctement la suite de l un des essais ci dessus corriger la tuyauterie d vac
33. be installed free standing in a utility room basement enclosed in an alcove or closet The extended flush jacket provides a pleasing appliance appearance installation Design certified by the American Gas Association AGA Laboratories and the Canadian Gas Association CGA Laboratories The productistruly designed with the contractor and consumer in mind The M2R C L Series covers all upflow and downflow applications The furnace uses hot surface ignition providing AFUEs in the 90 range from 40 000 to 120 000 Btuhs RIGHT SIDE BOTTOM 80 000 19 3 4 100 000 19 3 4 For Downflow model only Upflow models can be 1 The heat exchanger is atubular design made from aluminized steel The direct drive multi speed blowers range from 1 3 to 3 4 hp to handle any air conditioning application up to 5 Tons See Figures 1 amp 2 for overall dimensions CLEARANCES TO COMBUSTIBLE MATERIALS This furnace is designed for the minimum clearances to combustible material listed in Table 1 Refer to the furnace name plate located inside the furnace cabinet for specific model number and clearance information TOP LEFT SIDE BOTTOM 24 inches is the minimum clearance for servicing 36 inches is the recommended clearance for service Table 1 Minimum Clearances to Combustible Material suoisueuiiq HUN 9HcW L 4 Number Upflow Furnace Model ance Dimensions inches pns
34. bs under and uptightly againstthe supply air duct See Figure 11 Figure 5 Top View of Duct Connector OPENING TO DUCT REDUCER WITH PLATE C REMOVED OPENING BECOMES 13 1 4 x 13 1 4 SEE TABLE 3 SPACERS Figure 6 Duct Connector 11 12 20 14 1 2 lt 2 3 4 REAR WALL OF CLOSET OR ALCOWE 25 1 8 Upflow Models 21 7 8 Downflow Models Alt Fuel Line Hole FLOOR CUT OUT FOR DUCT CONN n n lt e LLI lt Figure 7 Cut Out Locations FLOOR OPENING CS FUEL m dl HOLE Figure 8 Closet or Alcove Floor Cut Out ________ 25 1 8 Upflow Models 1 21 7 8 Downflow Models of MOUNTING REAR WALL PLATE FLOOR OPENING ALT FUEL LINE HOLE CUT DUCT OPENING 1 16 LARGER THAN DUCT CONNECTOR Figure 9 Mounting Plate BEND CONNECTOR TABS UNDER DUCT OPENING MOUNTING OPENING ALT FUEL LINE Figure 10 Duct Connector 13 _ DUCT DUCT 1 INSERT DUCT PLENUM CONNECTOR 2 BEND BOTTOM TABS OVER INTO DUCT CUT OUT AND ONTO THE UNDERNEATH DUCT SERVICE Figure 11 Installation of Duct Connector NOTE The duct connector is designed for use on ducts 12 in width When using the connector on 12 wide ducts there Duct Connector may be insufficient clearance to bend the tabs
35. burner flame should carry over between all burners The flames should be blue without yellow tips Flames should extend from each burner without lifting curling or floating After verifying ignition set the thermostat below room temperature and verify that the burner flame extinguishes completely Verifying Operation of the Supply Air Limit Switch Toverify operation ofthe supply air limit switch make sure that the blower dooris in place and thatthere is power to the furnace Completely block the return airflow to the furnace by installing close off plate in place of or upstream of the filter s Set the thermostat above room temperature and verify that the Sequence of Operation is as described in these instructions The supply air limit switch should function to turn off the gas valve within approximately five minutes The circulating air and combustion blowers should continue to run when the supply air limit switch opens Remove the close off plate immediately after the supply air limit switch opens If the furnace operates for more than five minutes with no return air set the thermostat below room temperature shut off the power to the furnace and replace the supply air limit switch SYSTEM OPERATION INFORMATION General Proper maintenance is most important to achieve the best performance from a furnace Follow these instructions for years of safe trouble free operation Do not place combustible materials on or against the
36. chanical draft vent terminal Less than 10 ft Ge Air Inlet terminal more than 50 000 Btuh Figure 14 Vent Termination Clearances 18 Upflow Furnace Inlet Exhaust See Vent Table lt gt Seal Cualk Y around pipe _ Straps other suitable at building supports at minimum 5 foot intervals Z Z 90 Elbow Air Inlet Im Offset with Exhaust Pipe for Adequate Combustion Coupling Dimensional Clearance Muf set Upward Pitch 1 4 per Foot did ABS Outlet Exhaust Vent d Wall gt First Support located as close to furnace as possible Rubber Coupling w 2 Clamps Exhaust Vent Normal Snow Level A C Coil Box 3 Coupling Furnace Downflow Furnace Seal Caulk Vent Table 4 Around Pipe at Building Straps Other Suitable Supports at Minimum of x X 5 ft Intervals 90 Elbow SNAM S G Offset with Exhaust Pipe for Adequate Dimensional Clearance Upward Pitch 1 4 Per Foot Outlet Exhaust Vent lt Wall PVC or First Support Should be as Close to ABS pipe Furnace Connection as Possible Rubber Normal Snow Level Exhaust Vent Coupling and 2 Furnace Clamps Figure 15 Horizontal Venting 19 Upflow Furnace Rubber Coupling w 2 Clamps Combustion Air Pipe 3 Coupling Downflow Furnace Exhaust Vent Upflow Furnace Use appropriate
37. d now be read If not replace switch See Figure 44 I Possible causes of roll out switches tripping Blocked heat exchanger sooted Loose heat exchanger tube Burner misaligned Supply air interfering with flame patterns Overfiring too high gas pressure Insufficient combustion air 0 UI gs pu Figure 45 Draft Inducer Motor See Figure 46 All models use an induced draft combustion blower mounted on the outlet side of a secondary heat exchanger Its purpose is to establish a draft flow through the heat exchanger to insure that all flue products are carried outside the structure via the vent pipe See Figure 50 The blower 41 Figure 46 is made of plastic and is driven by a 115V permanent split capacitor motor The same part blower is used on all models of all series There is however a different size restrictor orifice for different BTU capacities mounted on the inlet back side of the blower When replacing a combustion blower it is essential to transfer the restrictor from the old housing to the new one before blower is mounted on collector box The only exception is the 40 000 BTU which uses the restrictor supplied All others are transferred See Figure 47 o Figure 47 Check out Procedure 1 Disconnect Molex plug between control board and motor 2 Using the appropriate scale on a volt meter insert probes into plug coming from control board 3 E
38. dyne Part 90 upflow 632252 90 downflow 632304 1 55 1 65 1 74 1 8 Switch Type diff dual port NO diff dual port NO Table 12 Secondary Heat Exchanger Primary Heat Exchanger Air Flow thru Heat Exchangers Burner Compartment Outdoor m Air Figure 50 Port to Burner Port to Exhaust j Compartment Blower Exhaust Blower Pressure Switch Cut a Way Figure 51 To test for proper differential install a differential pressure gauge magnehelic or equivalent or U Tube as shown in Figure 52 Follow check out procedure If sufficient negative pressure is being created reading is steady and vacuum hoses areclear replace pressure switch If sufficient negative pressure is not being created look for problems described in Table 13 Check out Procedure 1 Removeorange wires from pressure switch Place tees in the hose connecting pressure switch to burner box and collector box 2 Connecta Magnehelic or Inclined Manometer to tee Start induce draft motor 4 Negative pressure created by the induced draft motor must be greater than 1 75 W C for switch to close See Table 12 5 Useanohmmeterto check for continuity across switch 6 Ifcontinuity is established switch is closed If ohmmeter shows an infinite reading switch is open and must be replaced Ifthe pressure differential reading will not pull down to 1 75 W C 1 80 M2RL 040 060 then there could be sever
39. e lever knob must be moved to the end of its range of motion to insure the valve is completely open Use only your hand to push in or turn gas control valve Never use tools 5 Set the room thermostat to a point above room temperature to begin the heating cycle of the unit 6 Checkthatthe unitignites and operates properly Refer tothe installation instructions provided with your unit for the normal operating sequence 7 After the flame ignites visually inspect the burner assembly to ensure that the flame is drawn directly into the center of the heat exchanger tube as shown in Figure 25 The end ofthe flame will be out of sight around the bend of the heat exchanger tube In a properly adjusted burner assembly the flame color should be blue with some light yellow streaks near the outer portions of the flame PP Figure 25 Burner Inspection 26 NOTE Until all of the air is bled out of the gas line the hot surface ignitor may not ignite the gas If the ignition control locks out turn the thermostat to its lowest setting and wait one minute then turn the thermostat to a point above room temperature and the ignitor will try again to ignite the main burners This process may have to be repeated several times before the burners will ignite Oncethe burners are lit check all gas connections for leaks again with the soap and water solution If the solution bubbles there is a gas leak which must corrected Do not use a
40. e replaced Transformer See Figure 36 Thetransformer supplies control voltage 24 vac by stepping down the supply primary voltage from 115 vac to 24 vac secondary voltage Transformers are rated by VA VA is the volt amp or total wattage the secondary can handle Whenatransformeris replacedthe VA should be of an equal or greater value Figure 36 Check out procedure 1 Using volt ohmmeter on at least 115 vac scale 2 Measure the voltage on the control board terminals XFMR amp NEUTRAL If voltage is 115 vac measure the voltage at terminals marked 24 vac amp Com located in the center of the control board 115 vacis measured at XFMR amp NEUTRAL but no voltage is present at 24 vac amp Com replace transformer Transformers open primary indicate low voltage short circuit Transformers open on secondary indicate an overload a current draw that exceeded rating Control Board See Figure 37 The control board is manufactured by UTEC This control manages allfurnace functions It also serves as a diagnostic tool if the furnace should malfunction Figure 37 Features 90second delay blower off time in cooling mode LED B Diagnostics Low Voltage Fuse an over current short circuit safety device designed to protectthe control board in the event of a low voltage short or over current See Figure 38 Field Adjustable Fan Settings Heating Mode Figure 38
41. e hook ups are shown in Figure 22 When making the gas connection provide clearance between the gas supply line and the entry hole in the furnace casing to avoid unwanted noise and or damage to the furnace All gas piping must be installed in compliance with local codes and utility regulations Some local regulations require the installation of a manual main shut off valve and ground joint union external to the furnace The shut off valve should be readily accessible for service and or emergency use Consult the local utility or gas supplier for additional requirements regarding placement of the manual main gas shut off In the absence of local codes the gas line installation must comply with the provisions stated in the Federal Manufactured Home Standard H U D Title 24 part 280 and the National Fuel Gas Code ANSI Z223 1 NFPA 54 or CAN CGA B149 installation codes A 1 8 NPT plugged tap must be installed in the gas line to the unit for use when measuring the gas supply pressure The plug should be readily accessible for service use drip leg should be installed in the vertical pipe run to the unit Table 6 lists gas flow capacities for standard pipe sizes as a function of length in typical applications based on nominal pressure drop in the line NOTE Gas piping must notbe run in or through air ducts chimneys gas vents elevator shafts etc Compounds used on threaded joints of gas piping must be resistant to the actions of lique
42. ed 84 000 Btuh NOT use pipe joint compound on the orifice threads Screw the orifices into the manifold by hand until snug to eliminate cross threading then tighten with a wrench Before installing an orifice check the face or side of the orifice for the drill number to ensure that it is the appropriate size For the conversion to the alternate fuel the gas valve regulator cap must be turned over as shown in Figure 24 You will unscrew the cap and reinstall for your installation After reinstalling the cap you will be able to read NAT for the conversion to natural gas or LP for the conversion to LP gas Honeywell Valve OTHER SIDE OF CAP PRESSURE REGULATOR M ow 1 Figure 24 Convertible Pressure Regulator Cap Reinstallingthe Burner Assembly 1 2 Reinstall the gas manifold assembly to the burner box with the four 4 fasteners which were removed earlier Carefully reinstall the burner box into the unit After installing the burner inspect the alignment of the burners with the heat exchanger tubes The center of the burners should be aligned with the center of the tubes EXAMPLE 2 5 500 feet Propane M2RC100A 16 BN Elevation Type of gas Furnace model Orifice in Natural to LP Conversion Kit 55 drill What burner orifices are needed The required input for 5500 feet is 76 000 Btuh or 24 less than the sea level rating of 100 000 Btuh See Table 7 for LP gas find the Furnace Model
43. enting system are not in operation a Seal any unused openings in the venting system b Inspectthe venting systemfor proper size and horizontal pitch as required in the National Fuel Gas Code ANSI 2223 1 or the CAN CGA B149 Installation Codes and these instructions Determine that there is no blockage or restriction leakage corrosion and other deficiencies which could cause an unsafe condition c In so far as is practical close all building doors and windows and all doors between the space in which the appliance s connected to the venting system are located and other spaces of the building Turn on clothes dryers and any other appliance not connected to the venting system Turn on any exhaust fans such as range hoods and bathroom exhausts so they shall operate at maximum speed Do not operate a summer exhaust fan Close fireplace dampers d Follow the lighting instructions Place the appliance being inspected in operation Adjust thermostat so appliance shall operate continuously e draft hood equipped appliance spillage at the draft hood relief opening after 5 minutes of main burner operation Use the flame of a match or candle f After it has been determined that each appliance connected to the venting system properly vents when tested as outlined above return doors windows exhaust fans fireplace dampers and any other gas burning appliance to their previous conditions of use g lfimproper venting is observed
44. essories The bracketis installed on the right hand side at the top of the cabinet as shownin Figure 28 The bracket can be fastened using the self drilling screws supplied with A C Condensing Unit Condensing Unit Control Box Blower Off sonic 3 Amp Timing Fuse TWIN Flame Signal Light 5 Yellow Status Light Red Neutrals Unused Motor Leads Figure 27 Low Voltage Field Four wire Heating Cooling Applications 28 VentilAire Bracket Figure 28 Ventilation Bracket the unit For installation of the VentilAire or IV follow the instructions provided with the VentilAire kit For upflow models the means to provide the required ventilation must be incorporated into the upflow furnace base or the return air ductwork tothe furnace For installation ofthe VentilAire IIl or IV follow the instructions provided with the VentilAire kit START UP AND ADJUSTMENTS General Prior to start up verify that 1 The line voltage power leads are securely connected that the polarity of the connections is correct and that the furnace is properly grounded 2 The thermostat wires R W Y and G are securely connected to the correct leads on the terminal strip of the circuit board Thenaturalgas line service pressure must not exceed 10 0 in water column 0 36 psig and must notbe less than 4 5 in water column 0 16 psig For LP gas the line service pressure must not exceed 14 in water column 0
45. fied petroleum gases The main manual gas valve and main power disconnect to the furnace must be properly labeled by the installer in case emergency shutdown is required N CAUTION Do not use matches lighters candles or other sources of open flame to check for gas leaks NOTE When pressure testing gas supply lines at pressures greater than 1 2 psig 14 in water column the furnace must be disconnected from the gas supply piping system to prevent damage to the gas control valve If the test pressure is less than or equal to 1 2 psig 14 in water column the furnace must be isolated from the gas supply line by closing the manual shut off valve Typical Left Side Entry Upflow Burner Viewport Roll Out Limit A i Burner Assembly Ca Some Utilities Require Shut Off Valve to be 4 to 5 feet Above Floor Denotes field provided and Installed components Shut Off Valve gt with 1 8 NPT Plugged Tap Automatic Gas Valve with manual shut off Typical Right Side Entry Downflow Denotes field provided and installed components Automatic Gas Valve with manual shut off Ground Joint Some Utilities SS Require Shut Valve to be 4 to 5 feet Above Floor Wve Shut off Valve with 1 8 NPT Plugged Tap Burner Viewp
46. for voltage between the Hot Black wire and Ground wire of the supply circuit Reading should be Line supply Voltage if zero volts is read there is no ground or polarity is reversed Figure 34 Polarity and Ground Polarity and Ground The 2 furnace will not operate if loss of ground occurs Every effort should be made at the installation to provide a good ground If old 2 wire romex exists it should be replaced with a 2 wire w ground A cold water line could be used provided that the connection or grounding occurs before any di electricfittings and provided no plastic pipe is usedinside or outside the building Blower Door Switch The blower door switch is located near the center of the furnace See Figure 35 The switch is normally open and closes with the proper installation of the bottom door of the upflow models ortop inside blower door on downflow models Its purpose is to break the 115 vac power supply when the door is removed exposing the blower Figure 35 Check out procedure using ohm meter 1 Turn off incoming power supply 2 Disconnect the wires on the switch 3 With the switch at rest no continuity should be read 4 Nowdepressthe switch plunger the OHM meter should show continuity or 0 ohms If not replace switch 38 The switch can also be checked with the 115 vac power supply on If the switch is manually depressed and 115 vac is read across it then the switch is bad and must b
47. furnace cabinet or the vent pipe Donotstore gasoline or any otherflammable vapors and liquids in the vicinity of the furnace e Change or replace the air filters monthly during any period when the circulating blower is operating regularly Alwaysreplace the doors on the furnace after servicing Do notoperate the furnace withoutall doors and covers in place Avoidoperatingthe furnace when windows and doors are open COM Leads Connect Neutral Lead of Electronic Air Cleaner and or Humidifier Here Humidifier Tap 5 120 Neutrals Be sure that thermostat is properly installed and is not being affected by drafts or heat from lamps or other appliances Sequence of Operation Operating sequences for the heating cooling and fan modes are described below Refer to the wiring diagram Figure 33 and the low voltage field wiring diagram Figure 27 for more details Heating Mode 1 Onacallforheatthe thermostat closes applying 24 VAC to the W terminal on the control board 2 The control board checks for continuity on the 24 VAC limit control circuit over temperature limit switch flame rollout switches and blocked vent switch in series If an open limit is detected the control board will energize the inducer andthe conditioned air blower All other system functions will be inoperable until the limit circuit closes While the limit is open the red LED wil
48. h pressure drop of 0 3 in and specific gravity of 0 60 natural gas Nominal Length of Pipe in Feet Iron Pipe Size Inches 10 20 30 40 50 60 70 80 1 2 132 92 73 63 56 50 46 43 3 4 278 190 152 130 115 105 96 90 1 520 350 285 245 215 195 180 170 1 1 4 1 050 730 590 500 440 400 370 350 1 1 2 1 600 1 100 890 760 670 610 560 530 After the length of pipe has been determined select the pipe size which will provide the minimum cubic feet hour required for the gas input rating of the furnace By formula fF Btu h Cu Ft Per Hr Required 20 Heating Value of Gas Btu Ft3 The gas input of the furnace is marked on the furnace rating plate The heating value of the gas Btu Ft3 may be determined by consulting the local natural gas utility or the LP gas supplier LP Gas Pipe Capacity Table CU FT HR Maximum capacity of pipe in thousands of Btu per hour of undiluted liquified petroleum gasses at 11 inches water column inlet pressure Based on a Pressure Drop of 0 5 Inch Water Column Nominal Length of Pipe in Feet Iron Pipe Size Inches 10 20 30 40 50 60 70 80 90 100 125 100 1 2 275 189 152 129 114 103 96 89 83 78 69 63 3 4 567 393 315 267 237 217 196 182 173 162 146 132 1 1 071 732 590 504 448 409 3 8 346 322 307 2 5 252 1 1 4 2 205 1 496 1 212 1 039 913 834 771 724 677 630 567 511 1 1 2 3 307 2 299 1 858 1 559 1 417 1 275 1 181 1 086 1 023 976 866 787 2 6 221 4 331 3 465 2 992 2 646 2 394 2 205 2 047 1 921 1
49. he total free area of openings in the floor or ceiling registers serving the return air duct system must be at least 352 sq in Atleast one register should be located where it is not likely to be covered by carpeting boxes and other objects e Materials located in the return duct system must have a flame spread classification of 200 or less This includes a closet door if the furnace is in a closet f Noncombustible pans having 1 upturned flanges are located beneath openings in a floor duct system g Wiring materials located in the return duct system shall conform to Articles 300 22 of the National Electrical Code ANSI C1 NFPA 70 h Gas piping is not run in or through the return duct system i Testthe negative pressure in the closet with the air circulating fan operating at high speed and the closet closed The negative pressure is to be no more negative than minus 0 05 inch water column j For floor return systems the manufactured home manufacturer shall affix a prominent marking on or near the appliance where it can be easily read when the closet door is open The marking shall read N CAUTION HAZARD OF ASPHYXIATION Do not cover or restrict return air opening k Airconditioning systems may require more duct register and open louver area to obtain necessary airflow Use NORDYNE s certiduct program to determine proper duct size for A C Table 2 shows the airflow data for each furnace model 9 CAPACITIES
50. ied service technician to identify and repair the problem DESCRIPTION OF COMPONENTS Figure 33 shows the location of each of the functional components described below If any component of the furnace must be replaced use only factory authorized replacement parts Contact your distributorforthe approved replacement parts Flame Sensor The flame sensor acts to prove that flame has carried over from the ignitor to the opposite end burner If no flame is sensed the furnace will be shut down automatically Gas Valve The gas valve controls the flow of gas to the burners When the gas valve is energized it automatically opens and regulates the gas pressure in the manifold Pressure Switch The pressure switch verifies that the inducer is drawing the combustion gases through the heat exchanger It also senses a blocked condensate drain condition Vent Pressure Switch Downflow models only The vent pressure switch reacts to blockage in the vent or combustion air piping Supply Air Limit Switch The supply air limit switch prevents the air temperature leaving the furnace from ex ceeding the maximum outlet air temperature Vent Safety Switch The vent safety switch shuts the furnace down if the outlet flue gas temperature increases above 160 F This switch protects the plastic flue system and the inducer from over temperature conditions Flame Roll Out Switch This switch provides roll out protection t
51. ion clearances shown in Figure 20 are maintained 21 d No other gas fired appliances are vented through the chimney Exhaust Vent Elbow 1 Combustion Air _ 18 Min Intake 286 d 2299 Bro Plumbing Vent Roof Boot Typ Both Pipes Exhaust A 12 Above Roof or Snow Accumulation Level Figure 20 Vertical Vent Termination Vent Freezing Protection When the vent pipe is exposed to temperatures below freezing i e when it passes through unheated spaces chimneys etc the pipe must be insulated with 1 2 inch thick sponge rubber insulation Armaflex type insulation or equivalent Insulating pipe is important to avoid condensate icing For extremely cold climates or for conditions of short furnace cycles i e set back thermostat conditions the last three feet of vent pipe can be reduced one nominal pipe size provided that the total vent length is at least 15 feet in length and the vent is sized in accordance with the venting requirements Table 4 before this reduction is applied Example 3 to 2 1 2 Smaller vent pipes are less susceptible to freezing but must not be excessively restrictive A Collector Left Side Drain e Rotate counter g Step 2 Route to 8 J 4 Route to HARD J downward Loosen For Step 1 D Tub Retighten for Step 3 slope
52. is 90 feet with one elbow Select 3 pipe Fortwo additional elbows deduct 3 5 ft for each elbow or 7 0 ft fora maximum installed vent length of 83 ft Condensing furnace combustion products have very little buoyancy so Table 4 is to be used without consideration of any vertical rise in the piping NOTE Always use the same or larger size piping for combustion air as is used for the exhaust vent Vent Pipe Installation Pipe Routing and Support Route piping as directly as possible between the furnace and the outdoors and remember that routing affects pipe size requirements per the preceding section If atwo pipe system is used locate the combustion air intake and the vent exhaust in the same atmospheric pressure zone i e both must exit the building through the same portion of exterior wallorroof Vent piping mustbe sloped upwards notless than 1 4 per foot in the direction from the furnace to the terminal This is to ensure that any condensate flows back to the furnace where it can be disposed of through the condensate disposal system N CAUTION Combustion air must not be drawnfrom a corrosive atmosphere The quality of outdoor air must also be considered Be sure that the combustion air intake is not located near a source of solvent fumes or other chemicals which can cause corrosion of the furnace combustion system Piping must be mechanically supported so that its weight does notbearonthe furnace Supports
53. l pulse at a rate of 1 blink per unit time 3 The furnace control checks for continuity across the pressure switch 24 VAC If the pressure switch is closed the heat mode sequence will not continue If it remains closed for 10 seconds the red LED will blink 3 times repetitively until the fault condition clears 4 Theinducer is energized 5 The pressure switch will close If the pressure switch does not close after 10 seconds the fault LED will blink O O o 3 Amp Blower Off Timing TWIN Flame Signal Light Yellow Status Light Red Unused Motor Electronic Air Tap Cooling 5A 120 Speed Tap Heating Speed Tap Figure 29 Blower Speed Tap Location 31 2 times repetitively and the inducer will continue to run until the switch is closed 6 Theinducer will pre purge for 30 seconds and then the ignitor will start its warm up After 30 seconds of ignitor warm up the gas valve 24 VAC will open The ignitor circuit stays energized for 6 seconds after the gas valve opens 7 The furnace control must prove via the flame sensor six seconds after the gas valve opens If flame is sensed all burners are on and the ignitor cools off If no flame is sensed the gas valve closes immediately and the inducer continues to run A second trial for ignition step 6 begins if no flame is sensed On the fifth try for ignition the furnace control is locked out and the red LED will blink
54. ments for 2 pipe combustion air piping The capacity table provided in this section applies to the total sum of vent and combustion air piping lengths These condensing furnaces are classified as Category IV appliances which require special venting materials and installation procedures Category IV appliances operate with positive vent pressure and therefore require vent systems which are thoroughly sealed They also produce combustion condensate which is slightly acidic and can cause severe corrosion of ordinary venting materials Furnace operation can be adversely affected by restrictive vent and combustion air piping Therefore ventand combustion air piping lengths must conform completely to the requirements of Table 4 Thefurnace must be vented to the outdoors It must not be vented in common with any other appliance even if that 15 appliance is of the condensing type Common venting can resultin severe corrosion of other appliances or their venting and can allow combustion gases to escape through such appliances or vents Do not vent the furnace to a fireplace chimney or building chase If removing an existing furnace in a venting system the venting system may not be properly sized To test the vent system with the remaining appliances follow the test outlined below The following steps shall be followed with each appliance connected to the venting system place in operation while any other appliances connected to the v
55. mperature rise measured is outside the range specified it may be necessary to change the blower speed Lower blower speeds willincrease the temperature rise and higher blower speeds will decrease the temperature rise The furnace is equipped with a multispeed motor Heating and cooling speed selection is made by moving the leads on the integrated control board located in the furnace The wiring diagram on the furnace and Figure 29 show the speed taps for adjusting motor speed If itis desired that the blower operate at the same speed for heating and cooling tape off the terminal of the unused blower wire Install the jumper wire found in the plastic instruction bag across the HEAT and COOL taps on the 30 control board Reconnect the desired blower tap to the piggyback quick connect The blower control is designed to start the circulating air blower 30 seconds after the gas valve is opened The blower control is factory wired to turn the blower motor off 120 seconds after the gas valve is closed This timing can be changed using the BLOWER OFF timing switch opposite the terminal block on the control board See Figure 29 Verifying Burner Operation Toverify operation ofthe burners make sure thatthe blower compartment door is in place and that there is power to the furnace Set the thermostat above room temperature and observe the ignition sequence The flame can be observed through the small clear window on the burner box The
56. n open flame to check for gas leaks Adjusting the Manifold Pressure The manifold pressure can be measured by installing a pressure gauge or U tube manometer to the outlet end of the gas valve as follows 1 With a 3 16 Allen wrench remove the manifold pressure tap plug located on the outlet side of the gas valve Refer to Figures 30 amp 31 for more details 2 A fitting which has a 1 8 NPT pipe thread that is compatible with the pressure gauge or U tube manometer must be installed at this point 3 Install the pressure gauge or U tube manometer according to the manufacturer s supplied instructions 4 Set the room thermostat to a point above room temperature to start the furnace 5 Allow the furnace to operate for three 3 minutes and then check the manifold pressure 6 Table8liststhe appropriate manifold pressures for both natural gas and propane LP gas installations For the type of fuel and the altitude of your installation determine the required manifold pressure For Canadian high altitude installations refer to the High Altitude Derate section for more details Propane LP Manifold Pressure for 0 2000 3 5 Feet Above Sea Level In WC 10 0 Table 8 Manifold Pressures for Sea Level Completing the Conversion 1 Affix the gas valve conversion label found in the package with the orifices to the unit rating plate 2 Runthe appliance through a complete cycle to assure proper operation N CAUTION
57. ned above in inlet pipe Note burner box pressure opposes acts to open contacts on differential switch NOTE Blower Pressure Burner Pressure Differential Pressure Table 13 Lower lesser Differential Negative Pressure Than Closing Pressure Hot Surface Ignitor See Figure 53 The hot surface ignitor is helical in shape and is located approximately 3 16 in front of the burners Its function is to Figure 53 44 ignite fuel at the appropriate time in the sequence The hot surface ignitor used by NORDYNE is manufactured by CARBORUNDUM You will also find a flat M type ignitor also used They are interchangeable See Figure 53 NOTE Special care should be taken when handling the ignitor You should never touch the ignitor surface Grease or dirt from your hands will shorten the ignitor s life Check out Procedure 1 Unplug ignitor from 2 prong plug 2 Placeavoltmeter on the proper scale atleast 115 vac 3 Establish a call for heat 4 After approx 30 seconds of induced draft motor operation the ignitor should see line voltage If voltage is present replacethe ignitor See Figure 54 If no voltage is present replace control board Theignitor may also be ohmed out The ignitors usually range from 125 to 150 ohms at 70 F 21 C See Figure 55 8 Besure when replacement ignitor is installed that it is approximately 3 16 from the burners Mishandling and misalignment are reasons why the igni
58. nts 29 31 General 29 Start Up Procedure uuu u uuu u su sss 29 Shut Down Procedure 29 Verifying And Adjusting Firing Rate 29 30 Verifying And Adjusting Temperature Rise 30 Verifying Burner Operation 30 Verifying Operation Of The Supply Air Limit eene e 30 31 System Operation Information 31 32 General ETERNI 31 Sequence of Operation 31 32 Heating Mode 31 32 Cooling MOJE io oto 32 me 32 Furnace Fails To Operate 32 34 Component Parts 32 46 Description of Components 32 Location of Major Components 33 34 M2RC Upflow Furnace 33 M2RL Downflow Furnace 34 Troubleshooting Flow Chart 35 UTEC Control Board Sequence 36 Wining M 37 Polarity and Ground 38 Blower Door Switch 38 Trans Orim el 38 39 Gontrol L usaha 39 40 GOnIr6 S uu u 40 Main Air Limit Control
59. o the furnace and combustion air inlet pipe Upflow Furnace O ON O Q FP Cc N oF G N O 16 17 18 19 ONSE D Manifold Flame Sensor Not Shown Gas Valve Roll Out Limit Switch 155 F Pressure Switch Control Board Integrated Blower Door Switch Vent Safety Limit Switch 160 F Transformer Limit Switch Blower Assembly Inducer Blower with gasket J Trap Hard Tube In Line Drain Assembly Burner Box Assembly Nat and LP Gas Ready Header Outlet Box Cased CoilWrapper Filter 18 5 8 x 26 1 2 x 1 4 Not Shown Attachment Bracket Turbulator Not Shown Coupling Neoprene Orifice Inducer Not Shown Inshot Burner Not Shown Natural and LP Gas Orifice Not Shown Ignitor Not Shown Heat Exchanger Assembly Not Shown Capacitor Assembly 10 MFD 370V Not Shown Blower Wheel CCW Not Shown Motor 1 2 HP 4 Speed Not Shown Access Doors Set Not Shown SA A 9 9 s Figure 30 M2RC Location of Major Components 33 Downtflow CON OO Q N 10 11 12 13 14 15 16 17 18 19 21 24 N 8 31 34 Manifold Flame Sensor Not Shown Gas Valve Roll Out Limit Switch 155 F Pressure Switch Integrated Control Board Blower Door Switch Not Shown Vent Safety Limit Switch 160 Limit Switch Blower Assembly Inducer Blower with gasket J Trap
60. oid misalignment of the furnace combustion air piping and vent piping see Figures 15 17 on pages 19 amp 20 Installation procedures are suggested for typical furnace installations and need not be followed in exact listed sequence CUT OUT FLOOR OPENING FOR DOWNFLOW MODELS a Determine center of closet or alcove Figure 8 b Locate center of the floor opening measured 10 from If X Use Duct the rear wall and mark cut out measuring approximately Floor cavity is Connector Model 14 1 2 by 14 1 2 1 formodel duct connector used 7 8 22mm refer to Figures 7 amp 8 e CUT DUCT OPENING 4 1 4 108mm 901989 6 1 4 159mm 901990 Figure 4 Floor Cavity Cut Out a Place duct connector through the floor opening with bottom tabs resting on top of the supply air duct 8 1 4 210mm b Center duct connector and push back against rear 10 1 4 260mm edge of floor opening 12 1 4 311mm c Mark cut out location tab area and remove duct connector Table 3 Duct Connectors d Cutout duct opening 1 4 larger than area marked INSTALL FURNACE MOUNTING PLATE a Bendtabs on furnace mounting plate upwards 90 b Place mounting plate supplied within duct connector at rear of the floor opening See Figure 9 INSTALL DUCT CONNECTOR a Place duct connector through the floor opening with bottom tabs extending through the duct opening See Figure 10 b Secure duct connector to floor c Bendbottomta
61. on requirements 1 Thetermination mustbe 12 inches above snow level or grade level whichever is higher See Figure 18 for alternate method to achieve 12 above snow level 2 he minimum distance for a direct vent 2 pipe installation from any door openable window or air gravity inletis 1 ft below 1 ft horizontally or 1 ft above Theventtermination shall be a minimum of 3ft above any forced air inlet within 10 ft 4 The vent termination shall be located at least 4 ft horizontally from any electric meter gas meter Direct vent terminal 50 000 Btuh or less Mechanical draft vent terminal regulator and any relief equipment These distances apply ONLY to U S installations In Canada the Canadian Fuel Gas Code takes precedence 5 Avoid areas where condensate drainage may cause problems by dropping on planters or patios etc Also ensure that exhaust gases will not impinge on windows or building surfaces which may be compromised or damaged by condensation Do not install the vent terminal such that exhaustis directed into window wells stairwells under decks or into alcoves or similar recessed areas and do not terminate above any public walkways 6 Selectthe point of wall penetration where the minimum 1 4 inch per foot of slope up can be maintained N CAUTION For optimal performance vent furnace through wall which experiences the least exposure to winter winds Mechanical draft vent terminal Me
62. on two sides of the duct connector In such cases the tabs may be attached to the sides of the duct by using sheet metal screws or other suitable fasteners See Figure 12 If tape is used to provide a better seal it should be approved by applicable national or local codes Dici ALTERNATE ATTACHMENT METHODS This procedure may also be used to install a furnace duct connector to narrow metal ductwork where insufficient clearance prevents bending of the duct connector tabs atthe Figure 12 Narrow Duct Installation side s of the duct See Figure 13 Fold Back Flap B Fold Back Flap B Cut Cut Out Cut Out Top of Duct Fold Back Flap B Fold Back Flap B Staple Folded Duct Bend Duct Connector Tabs Up Flap typ to side of Duct and Over along length of duct Connector Figure 13 Alternate Installation 1 Score and cut the top the metal duct as indicated Step 1 or Step 2 With Step 1 choice also cut out the metal from the shaded area A 2 Fold the duct flap B up See Step 3 3 Atthefront to back of ductrun Area A bendthe duct tabs and secure them directly to the duct 4 bend the ducttabs up and back over around the duct connector See Step 3 5 Fold form the duct flap against the side of the duct connector and attach as shown See Step 4 Use three 3 staples minimum on each duct flap OR if a 2X block joist is not provided use two 2 sheet
63. oor drain OR Route to condensate pump Keep downward slope Clamp Loosen For Step 1 Retighten for Step 3 HARD J Drain Tube Figure 21 Furnace with Condensate Drain Trap Assembly 22 condensate should from the plastic collector box location A in Figure 21 as droplets or a small stream If you notice the furnace has operated for more than 5 minutes without draining or the red status light on the control board is pulsing a 2 blink code follow the steps below 1 Remove the collector box soft tube at location A in Figure 21 and insure the exit from the collector box is clear of any debris or obstructions 2 Replace this tube and insure the fit to the header spout is air tight Air will be drawn into the header if this connection is not tight Check other tube connections along the drain system Insure that all are air tight NOTE Industry research studies indicate that when condensate is routed to an active drain household detergents etc buffer its acidity If the drain is not actively used or if codes require obtain a neutralizer kit usually contains limestone Proper drains and connections to the condensate tubing are required as NORDYNE cannot be held responsible for water leakage which occurs due to loose hose connections or improperly sealed drain line pipes GAS SUPPLY AND PIPING General This furnace is equipped for either left or right side gas entry Typical gas servic
64. ort Figure 22 Typical Gas Service Connection 23 CAPACITY OF BLACK IRON GAS PIPE CU FT PER HOUR FOR NATURAL GAS SPECIFIC GRAVITY 0 60 NOMINAL LENGTH OF PIPE RUN BLACK IRON feet PIPE mor 50 60 70 L e ol 7s e 55 50 45 40 8 4 280 190 150 130 115 105 95 90 The cubic feet per hour listed in the table above must be greater than the cubic feet per hour of gas flow required by the furnace 1 1 1 2 To determine the cubic feet per hour of gas flow required by the furnace divide the input rate of the furnace by the heating value of the gas Cubic Feet Per Hour Required Input To Furnace Btu hr Heating Value of Gas Btu Cu Ft Table 6 Capacity of Black Gas Pipe cu ft per hour for Natural Gas specific gravity 60 Leak Check After the gas piping to the furnace is complete all connections must be tested for gas leaks To check for leaks use only a soap and water solution or other approved method High Altitude Derate The nameplate input rating for the furnaces apply for elevations up to 2 000 feet 610m above sea level For elevations over 2 000 feet reduce the input by 4 for each 1 000 feet above sea level For example a furnace applied atan elevation of 5 000 feet should be derated by 2096 See Table 7 describing the correct orifice for derate NOTE For Canadian high altitude 2 000 to 4 500 ft simply reduce the gas manifold pressure to 2 8 W
65. oses within blinks 2 times Replace 10 seconds pressure switch Yes No Pressure switch 15 there gt 8mA on W terminal open of circuit board Replace t stat or add isolation relay Yes No Greater than Check venting 1 75 W C differential at pressure switch Yes Replace pressure switch Inducer prepurges for 30 seconds Ignitor heats up No Check for voltage Replace circuit board and glows for at molex plug 30 seconds Yes Yes Replace ignitor gt 24 volts at gas valve Insure lever is in ON position Insure gas inlet pressure is below 14 W C Yes Replace gas valve No Manifold Gas No Do Burners Light Pressure Available Yes Check and adjust ignitor to 3 16 No Flame light on Clean flame sensor with steel wool Check ground circuit to Furnace Flame light blinks at 1 signal Gas valve open Yes Yes Flashing Replace board Ignitor turns off 7 seconds No Replace circuit board after gas valve opens Yes Check for voltage at No soni and puch a Yes Check motor and capacitor Flame inducer main blower stay on until call for heat ends 35 seb sye 0 paun si JeMo q eu 06 191JV 2 peuJni si BY spuo5 s 0 191JV Z pauan SI 526 M 0 H L uMO p in
66. prevent entry of water When the above kits are not used the following steps are required 1 Checkthe hole size cut through the exterior wall Insure that the hole diameter is less than the diameter of the couplings to be used 2 Extendthe vent pipe through the wall approximately 1 and seal the area between the wall and pipe 3 Apply couplings to the vent pipe on the interior and exterior sides of the wall to insure the pipe can not be pushed or pulled through the wall 4 Insure the combustion air inlet pipe has 90 degree termination elbow and is pointing downward as shown in Figures 19 amp 20 Note that a combustion air intake must be provided with an elbow opening downward When the vent pipe must exit an exterior wall close to the grade or expected snow level a riser should be provided as shownin Figure 18 Insulation is required to prevent freezing of this section of pipe Vertical Venting Figure 20 shows the proper installation and clearances for vertical vent termination The roof penetration must be properly flashed and waterproofed with a plumbing roof boot or equivalent flashing Termination spacing requirements from the roof and from each other must be per Figure 20 Vent and combustion air piping may be installed in an existing chimney which is not in use provided that a Both the exhaust vent and air intake run the length of the chimney b Thetop of the chimney is sealed and weatherproofed c The terminat
67. re must be set at 10 0 in water column for use with LP gas To adjust the manifold pressure remove the regulator cap and turn the adjusting screw clockwise to increase pressure or counterclockwise to reduce pressure Replace the regulator cap after adjustments are complete 29 GAS FLOW RATE CUBIC FEET HOUR CUBIC FEET PER REVOLUTION OF TIME FOR ONE REVOLUTION SECONDS 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 TIME FOR CUBIC FEET PER REVOLUTION OF ONE REVOLUTION METER SECONDS 1 5 100 _ Table 10 Gas Flow Rate Verifying and Adjusting Temperature Rise Verify thatthe temperature rise through the furnace is within the range specified on the furnace rating plate Temperature rises outside the specified range could result in premature heat exchanger failure Place thermometers in the return and supply air stream as close to the furnace as possible The thermometer on the supply air side must be shielded from direct radiation from the heat exchanger to avoid false readings Adjust all registers and duct dampers to the desired position and run the furnace for fifteen minutes before taking any temperature readings The temperature rise is the difference between supply and return air temperatures For typical duct systems the temperature rise will fall within the range specified on the rating plate with the blower speed at the factory recommended setting If the te
68. rgized and the induced draft and main blower motors continue to run The main limit will automatically reset after the temperature is reduced Figure 43 Check out Procedure 1 Shutoff power to furnace 2 Remove wires from limit Be sure furnace has removed any heat surrounding switch Check for continuity across switch a Ifcontinuity is present switch is closed and assumed good b If continuity is infinite the limit is open and should be replaced Limits should be replaced with their exact replacement Check out can also be performed using a voltmeter a Put meter on at least 24 vac scale b Avoltage reading across the switch indicates an open switch Possible causes for Main Limit Tripping Dirty filter Dirty cooling coil Oversizedfurnace Restrictive duct system Main blower failure Improper speed selection Over firing of furnace gas pressure too high Main or induced draft motor cycling on internal overload SR NEP I Pr Roll Out Limit Control See Figure 42 The function of a roll out switch is to sense any flames backing out ofthe heat exchanger tubes They are normally closed and are manually reset Check out Procedure 1 Shutoff power supply to furnace Remove wires from roll out switch Using an ohmmeter check out continuity across switch Aninfinite reading indicates an open switch See Figure 45 5 Depress reset button to reset switch 6 Continuity or O ohms shoul
69. rmination can cause recirculation of the flue gases This may result in furnace vibration In severe cases the furnace will cycle due to the intermittent contact between the flame and the flame sensor If you note these oscillations occurring check the vent configuration Make sure that the exhaust vent does not have a 90 degree termination Exhaust Vent Option B i Mounting e e Faceplate Secured to Wall with Screws CK 18 Min Combustion det een Air Inlet e x Exhaust Vent Option C Exhaust Vent Option A 12 Min to Normal Snow Level Figure 19 Exhaust and Combustion Air Pipe Clearances For horizontal venting one of the following kits is recommended 3 PVC Horizontal Exterior Vent 9023750 Mounting Kit Neutralizer Kit Models 9023770 For Canadian installations please refer to the Canadian Installation Code CAN CGA B149 1 or2 and orlocal codes The kit consists of two face plates and an insulating gasket to seal the exterior surface A hole sized closely to the pipe diameter must first be cut through the wall A short length of pipe is then cut such that it can penetrate the wall and be held in place by closely fitting standard couplings The face plates are retained on both sides of the wall by the couplings and the gasket is retained against the wall by the outer face plate Face plates must be fastened to the wall and the outside one must be flashed as appropriate to
70. stablish call for heat 4 If voltage is read check fan capacitor If fan capacitor is okay replace motor 5 Ifno voltage is read replace control Pressure Switch See Figure 51 AIl M2R C and L use adifferential type pressure switch The purpose of this switch 1 to insure that a draft has been 42 Plastic Figure 49 established through the heat exchangers See Figure 50 The combustion blower creates a differential in negative pressure less than atmospheric between the inlet side of the combustion blower and the inside of the burner box of the furnace This switch is normally open and closes on a drop in pressure read in negative inches of water column See Table 12 Once the ventor motor builds up to speed and under normal operation conditions sufficient differential negative pressure will be created to close the differential pressure switch and keep it closed for the whole heating cycle Under abnormal conditions such as vendor motor failure or restricted vent pipe combustion air pipe leak around vendor assembly or water drainage problem sufficient differential pressure will not be created This condition will cause a 2 flash fault code on the board and ignition will not take place Under most circumstances when the pressure switch is not going closed insufficient differential negative pressure is not being created See Table 12 for open and close setting Settings Open Close Application Nor
71. tandard for the Installation of Air Conditioning and Ventilating Systems No 90A or the Standard forthe Installation of Warm Air Heating and Air Conditioning Systems NFPA No 90B RETURN AIR PROVISIONS Upflow models draw the return air from the base of the furnace A stand or return air duct must be supplied to the furnace to provide the required return air Downflow models draw the return air from the top of the furnace The minimum required clearance to the top of the furnace is detailed on the furnace rating plate Additional clearance may be required depending upon filter accessibility For each application the U S A home manufacturer shall comply with all of the following conditions to have acceptable return air systems for closet installed forced air heating appliances Heating Capacity Input BTUH 000 To Fuel Type N Natural e Width 19 3 4 Gas Ready L Propane LP Gas Ready Ss 1600 CFM Electrical mu A 60 Hz 120 a Regardless of the location the return air opening into the closet shall not be less than specified in the appliance s listing b Means shall be provided to preventinadvertent closure by a flat object placed over the return air opening when itis located in the floor of the closet versus the vertical front or side wall c The cross sectional area of the return duct system leading into the closet shall not be less than 390 square inches d T
72. the same with the exception of certain controls that are unique to a particular model This manual therefore will deal with all subjects in a general nature I E all text will pertain to all models unless that subject is unique to a particular model or family in which case it will be so indicated It will be necessary then for you to accurately identify the unit you are servicing so you may be certain of the approved diagnosis and repair See Unit Identification on page 9 This manual was prepared by the senior Technical Service and Communication Departments NWARNING The information contained in this manual is intended for use by a qualified service technician who is familiar with the safety procedures required in installation and repair and who is equipped with the proper tools and testing instruments Installations and repairs made by unqualified persons can result in hazards subjecting the unqualified person making such repairs to the risk of injury or electrical shock which can be serious or even fatal not only to them but also to persons being served by the equipment If you install or perform service on equipment you must assume responsibility for any bodily injury or property damage which may result to you or others We will not be responsible for any injury or property damage arising from improper installation service and or service procedures GENERAL The extra high efficiency upflow and downflow gas furnaces may
73. to closet or alcove framing VENTING AND COMBUSTION AIR REQUIREMENTS N CAUTION Snow must not be allowed to restrict or block the combustion air intake or vent pipes General NORDYNE condensing furnaces must be installed with outdoor combustion air piped directly to the furnace Codes refer to this type of installation as direct vent or two pipe installation Provisions must be made for adequate supply of air for combustion and ventilation For United States installations the adequacy of air provisions can be determined by consulting the current version of the National Fuel Gas Code ANSI Z223 1 NPFA 54 For Canadian installations requirements are specified in the National Standard of Canada CAN CGA B149 1 amp 2 Consult local codes for special requirements NOTE If the furnace is operated without adequate air for combustion and ventilation it may not perform properly Furnace components may be strained by high temperature and could fail prematurely NWARNING The combustion air piping must not be blocked or restricted in any manner NWARNING Furnace installation using methods other than those described in the following sections must comply with the National Fuel Gas Code and all applicable local codes to provide sufficient combustion air for the furnace VENTING REQUIREMENTS NWARNING FURNACE MUST NOT BE COMMON VENTED WITH OTHER APPLIANCES General This section specifies installation require
74. tor could fail Gas Valve Figure 56 The M2seriesfurnacesuse Honeywell valve VR8205A2008 Gas valves are 24 vac operated There are ports on the valves to read incoming supply pressure and manifold or burner pressure Supply pressure for natural gas should be 5 7 W C LP gas should be 11 13 W C Manifold pressure for natural gas should be 3 2 W C see Figure 57 and LP gas should be 10 W C see Figure 56 Check out Procedure 1 By using a volt meter on a 24 volt scale position the probes at the gas valves 2 Establish a call for heat Figure 56 3 Afterfurnace has operated for approximately 60 seconds the gas valve receives 24 vac from the control board Figure 54 See Figure 58 4 Ifgas valve does not open verify gas inlet pressure is available and not above 14 W C then replace valve Note High inlet gas pressure will lock down valve 5 Voltage may also be checked at the control board 6 Ifvoltage is not available at the control replace control Gas valves have a resistance of 1 9 to 2 mega ohms This coil may be open or shorted Figure 55 Figure 57 45 Figure 58 Sensor Figure 59 The sensor is located in front of the first burner After the burners are ignited flame is proven through the flame sensor by flame rectification The sensoris alloy consisting of aluminum chromium and iron This alloy is commonly known
75. uS IS ULION 2 06 s eum peziDJeue 1 eu spuooes oe JOLY p 4 jou SI awe Ji Spuooes p z Bi u p aq se spuooes 9 15 9u1 uo s 526 ay poled dn jeou puooes oe 1 y 44 0 e Z p zIiBu u 9 s SUL M O1 H 9501 L JONSNOAS NMOG LNHS 08S eur p sde 3 08S eur pesde 3 Jeonpu 081 06 09 OL lqelsn pv 99S Ocl 195 Alope4 SED 7779 M 91 H 1815 1 uMoq inus dn ueis ADNANOAS 1OHINOO S9a1n ADNANOAS dN LYVLS TVINHON Jeonpu 91 H jeoH 104 2 UO 1815 1 ue 3 Figure 32 UTEC Control Board Sequence 36 BLOWER SUPPLY AIR FLAME ROLL OUT VENT PRESSURE y DECK SWITCH LIMIT SWITCH SWITCH SAFETY SWITCH PRESSURE SWITCH SELECT MODELS ALL MODELS ALL MODELS SWITCH 93 MODELS ONLY ONLY ALL MODELS BLUE BLUE ORANGE ORANGE WHITE BLACK BLACK 120V BLOWER DOOR SWITCH Q ROOM THERMOSTAT LEE TRANSFORMER WHITE W BLK STRIPES senses e T 120 V 1 1 W WHITE STRIPES Cem d d 1 BLOWER OFF o
76. uation Vent Pipe Material Vent and combustion air pipe and fittings must be one ofthe following materials and must conform to the indicated ANSI ASTM standards Material Standard Schedule 40 PVC D1785 PVC DWV D2665 SDR 21 D2241 amp SDR 26 ABS DWV D2661 Schedule 40 ABS F628 Cement and primer must conform to ATSM Standard 02564 for PVC and Standard D2235 for ABS When joining PVC piping to ABS use PVC solvent cement See procedure specified in ASTM Standard 03138 Vent Pipe Length and Diameter In order for the furnace to operate properly the combustion air and vent piping must not be excessively restrictive To ensure this use Table 4 which indicates the maximum allowable piping length for a furnace of specified input rate wheninstalled with piping of a selected diameter and number of elbows Thistable applies to the length and number of elbows for each pipe To use the table the furnace input rate the centerline length and the number of elbows on each pipe must be known Choose the diameter for which the tabulated length is equal or greater than required Use of the table is illustrated in the following example Example An 80 000 Btuh furnace is to be installed in a two pipe system with 40feetof vent piping There arefour elbows excluding those exterior to the building Solution Consulting Table 4 in the dual pipe length column for an 80 000 Btuh furnace the maximum allowable length for a 3 inlet 3 outlet

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