Bryant 394B&D User's Manual
Contents
1. TO HEATING AND COOLING CONNECTIONS OF THERMOSTAT Lugo A73117 Figure 3 Control Box Cover Removed No Internal Wiring Changes The 175 000 Btuh belt drive and 200 000 Btuh units are equipped with a Honeywell fan limit control It provides control of fan operation and high limit tem perature protection The fan switch makes contact to start the blower motor on temperature rise to set point The limit switch breaks the circuit to the burn ers when the temperature rise reaches the set point Thermostat Location The room thermostat should be located where it will be in the natural circulating path of room air Avoid locations where the thermostat would be exposed to cold air infiltration drafts from windows doors or other openings leading to the outside or exposure to air currents from warm or cold air registers or to ex posure where the natural circulation of the air is cut off such as behind doors above or below mantels shelves etc The thermostat should not be exposed to heat from nearby radiators fireplaces radios televisions lamps or rays from the sun Nor should the thermostat be mounted on a wall containing pipes or warm air ducts or a flue or vent that could affect its operation and prevent it from properly controlling the room temperature Any hole in the plaster or panel through which the wires pass from the thermostat should be adequately sealed with suitable material to prevent drafts from af2. bimetal element 394B amp D Size 50 thru 200 Series A DISCHARGE OPENING 13 D RETURN AIR 19 16 1 OPENING la o 5 237 Toia SE EEE eored 2 283 32 soe X3 1 l RETURN as Hee a LAN ADA CON ane DROP t04 puct A da 1 28 23 4 3 B ds de ale PE 4656 23 If oe cera fees N AIR IL ER OPENING 355 3 VOLTAG o J id Hee BOTTOM 237 A RETURN OPENING X26 gt Figure 2 DIMENSIONAL DRAWING Table I DIMENSIONS IN INCHES Vent Cc Dia o sis 103 8 91 12 141 2 SS AE MODEL amp SIZE 394DAC000050 46 3 16 10 3 8 9 1 2 14 1 2 394DAC024050 46 3 16 10 3 8 9 1 2 14 1 2 394DAC000080 14 3 16 46 3 16 12 9 16 11 11 16 14 1 2 12 394DAC024080 14 3 16 46 3 16 9 16 11 11 16 14 1 2 394DAC036080 14 3 16 46 3 16 12 9 16 11 11 16 14 1 2 394DAC000100 17 1 2 46 3 16 15 7 8 he A 14 1 2 12 4 12 15 14 1 2 7 49 18 7 9 9 8 394BAD060175 g11 2 49 297 8 PE 394BAD060200 31 1 2 29 7 8 T Table li RATINGS AND CAPACITIES Temp Heating Cooling MODEL mean Output Btuh Range Pressure Pressure CFM E Sooo jo sooo OF ee a DE Ese A See eel 80 000 64 000 0 12 EE EA EA 100 000 80 000 0 15 ITA NE ee 125 000 100 000 0 2 394DAC000150 ee EN EE SHES 150 000 120 000 0 2 a o00 O NOS 175 000 140 000 0 5 0 5 A72591 TO CONDENSER CONTACTOR COIL CONNECTIONS
3. or 8D on heating speed 3D When the thermostat is satisfied the circuit between terminals 4 and W is broken deenergizing SEQUENCE OF OPERATION COOLING automatic gas valve coil 5A and heat assist coil When the thermostat calls for cooling power from 2G After a few seconds automatic gas valve 5A transformer 1A energizes cooling relay coil 2C closes stopping the flow of gas to the burners After a closing its contacts and energizing blower motor 3A longer delay heating relay 7J opens its contacts to 3B or 3D on its cooling speed It continues to operate stop blower motor 3A 3B or 3D until the thermostat is satisfied NS A
4. the circuit to ter minal G is broken deenergizing cooling relay coil 2C which in turn opens its contacts stopping blower motor 3A 3B or 3D 5A Gas Valve x 6A Pilot None on LP l j 7H Limit Control SPST N C ae 7J Fan Control SPST N O If any of the original wire as supplied must be replaced use same type or equivalent wire A73053 A73052 Figure 12 50 000 Btuh Unit with D2 or D5 controls Figure 13 50 000 Btuh Unit with D2 or D5 Controls no cooling fan relay cooling fan relay SEQUENCE OF OPERATING HEATING an additional period of time heating relay 7J closes When the thermostat calls for heat the control circuit its contacts energizing blower motor 3A 3B or 3D is closed between terminals 4 and W Power from if not already operating on heating speed The fur transformer 1A energizes automatic gas valve coil nace will continue to cycle until the fault is corrected 5A and heat assist coil 2G simultaneously After a The pilot 6A must be lit closing its contacts before short time delay automatic gas valve 5A opens per the gas valve 5A will open If for some reason the mitting gas to flow to the burners where it is ignited gas valve does not open when thermostat calls for by the gas pilot After another delay the heating relay heat heat assist coil 2G causes heating relay 7J to switches its contacts 7J energizing blower motor close its contacts energizing blower motor 3A 3B or 3A 3B
5. A yee Installation Instructions INTRODUCTION Before installing the furnace refer to Procedure for Gas Furnace Installation packaged with the equip ment for information concerning combustion vent ing piping and other standard installation practices Further reference is made to the current edition of the American National Standard Installation of Gas Appliances and Gas Piping Z21 30 Model 394 Gas Furnaces are shipped from the factory completely assembled and wired ready for indoor heating installation They are manufactured with two types of blowers belt and direct drive The four smaller sizes 50 80 100 and 125 are direct drive only All sizes incorporate a low voltage terminal strip for convenience of field wiring except 50 000 Btuh unit with complete shutoff gas controls This publication covers installation start up and maintenance For accessory installation details refer to applicable installation literature y The design of the 394B amp D Upflow Gas Fired Fur naces is A G A certified for installation on com bustible flooring in alcoves basements closets or utility rooms CLEARANCE REQUIREMENTS in inches BACE ic ii 0 Top Of Pionu al 1 Vent Connector single wall ooonn ococonnnnoninununcocinnno 6 Type B double wall unid di 1 ETON Doenan vata ohn canes ee cena 6 Provide service clearance of 30 in at front of unit Bryant Automatic Gas Control Valve N
6. OTE On units equipped with an A 643 Bryant automatic gas control valve there are three positions for the manual valve knob OFF PILOT ON There 1s a position stop at the PILOT position To move the manual valve knob from the PILOT position to either ON or OFF position the manual valve knob must be depressed 39394D76 2 15 73 A72548 Figure 1 Model 394D If not already checked when lighting the main burn er check the proper operation of this valve by moving the room thermostat pointer above and below room temperature and observing that the main burn ers light on call for heat and go off when the pointer is moved below the room temperature setting All Bryant automatic gas control valves have a delay when opening or closing Fan Limit Control Operation At the moment the thermostat calls for heat the time delay mechanism of the control is energized If due to pilot outage the control bimetal element does not sense a temperature change the control will turn on the blower strictly by means of the time delay feature If for any reason the time delay is not energized as the thermostat calls for heat the control bimetal element will bring on the blower when it senses a temperature rise of 50 degrees Fahrenheit standard differential above the turn off setting During the blow down period and after the thermostat is satisfied the con trol will turn the blower off at the indicated setting sensed by the control
7. ary c engages dimple in heating element and tighten screws carefully Replace draft diverter and vent con ia a SA BANS or i nte N H S o SR A coe ae oe sa persons on Le nector Replace manifold and burners Connect gas and electricity Test for gas leaks Care of Blower and Motor For long life economy and high efficiency clean ac cumulated dirt and grease from blower wheel and motor annually Also clean around bearings and shaft s of blower and motor See label on blower for oiling instructions Belt Tension Adjust tension on a V belt so that the belt deflects ap proximately 3 4 to 1 inch when the pressure from one finger is applied midway between the blower and motor pulleys Filters Each furnace is shipped with a Duralast permanent ATININ filter Check every 30 to 60 days See label on blower Figure 7 Removing Baffles for cleaning method It is not necessary to spray filter with oil PILOT Cleaning Heat Exchanger Pilot should be checked and cleaned if necessary at If it becomes necessary to clean heat exchanger the beginning of each heating season Pilot flame because of carbon deposits soot etc shut off gas should be high enough for proper impingement of the and electricity Remove burners and manifold assem safety element and to light the burners Remove ac cumulation of soot and carbon from thermocouple bly Remove vent connector and draft diverter safety element if used Remo
8. fecting the thermostat TO CONDENSER LOW VOLTAGE LEAD OR TERMINAL STRIP TO HEATING AND COOLING CONNECTIONS OF THERMOSTAT NOTE WIRE WITH IN FIGURE 3 IS REMOVED AND DISCARDED WHEN CONDENSER HAS TRANSFORMER A73118 Figure 4 Control Box Cover Removed Showing Internal Wiring Changes Set the thermostat heat anticipator as follows Units with Bryant A 641 or A 643 gas valve set at 0 5 Units with Robertshaw 7000 gas valve set at 0 3 ex cept 175 000 and 200 000 Btuh belt drive units set at 0 2 If additional controls are connected in the thermostat circuit the amp draw must be added to these settings Failure to make the settings will result in improper operation of the thermostat ELECTRICAL CONNECTIONS Low Voltage Wiring Field low voltage connections are made at the low voltage terminal strip See Figure 3 For Model 394 Furnaces used in conjunction with electric or gas air conditioning units that do not have an integral trans former see Figure 3 If the 394 Furnace is used in con junction with an electric or gas air conditioning unit having an integral transformer see Figure 4 Figure 4 shows a field installed wire running from one side of the air conditioning transformer through the hole marked F in the terminal strip to the blower relay in the control box for the Model 394 Fur nace The wire marked in Figure 3 is removed from the control box and discarded NOTE For heating onl
9. in the holes provided one in the blower deck and the other in the retainer spring bracket See Figure 6 When the side inlet is used the bottom opening should be properly and permanently sealed NOTE Side inlet application of the following units requires use of the appropriate optional external filter rack 048100 060125 060150 060175 and 060200 See instruction packed with filter rack for in stallation WARNING OW ARHING et AO _ gt DURALAST oo FILTER o PEA EN A A73116 Figure 6 Filter Installed For Side Inlet NOTE Some units with direct drive blowers have a shipping bracket See Figure 5 This bracket should be removed and discarded Belt drive units have wood shipping blocks that are to be removed and discarded START UP AND ADJUSTMENT In addition to the following information refer to Procedures for Gas Furnace Installation packaged with the unit Adjustment of Blower Speed Four Speed Direct Drive To change motor speed taps remove the motor tap lead see Figure 5 and relocate it on the desired ter minal on the plug in terminal block speed selector located on the blower Table HI SPEED SELECTOR Belt Drive The blower speed may be changed by opening or closing the motor pulley When adjusting blower speed be certain that the pulleys are properly aligned dala i be SOL ERONCE i Replace flue baffles Make certain that rear of baffle Le e pono
10. ve flue baffles from upper heating element flue outlets by removing two screws that secure baffles in It is recommended the pilot be turned off during the place Clean flueways with brush and or vacuum summer season THERMOSTAT CONNECTIONS HEATING ONLY Units with Non 100 Shutoff Controls Units with 100 Shutoff Controls Natural Gas Natural or LP Gas NOTE REMOVE INTER NAL JUMPER BETWEEN WEJ TERMINALS T87F and subbase P N 34427D28 Thermostat Model 885 or 886 886 requires subbase P N 34427D36 Thermostat Model 883 883A 884 884A or 886 A68372 A68372 AG8372 Figure 8 Field Wiring Connection 5 LINE TO LINE WIRING DIAGRAMS A73051 ATS114 Figure 10 Units with 1 6 1 3 1 2 or 3 4 HP Direct Drive Motor cooling fan relay No Capacitor on 1 6 and 1 3 HP A73050 Figure 11 Units with 3 4 HP Belt Drive Motor Figure 9 Units with 1 10 1 6 or 1 5 HP Direct cooling fan relay Drive Motor no cooling fan relay Motors If the furnace overheats for any reason limit control 7H will switch breaking the circuit to automatic gas valve coil 5A After a short delay the gas valve closes shutting off the flow of gas to the burners After 6 LEGEND 1A Transformer 2A Cooling Fan Relay 2C Cooling Fan Relay 2G Heating Fan Relay 3A Fan Motor SP PH 3B Fan Motor SP 3D Fan Motor PSC 4A Capacitor None on 1 6 amp 1 3 HP Motors When the thermostat is satisfied
11. y connections See Figure 8 po o Line Voltage Wiring All electrical connections are to be made in ac cordance with the local electrical codes A permanent live separately fused electric power supply complete with manual switch should be provided for the fur nace Field wiring connections should be made in ac cordance with the unit wiring diagrams When making aluminum conductor connections to copper conductors or terminals use only connectors that are UL approved marked Al Cu with the UL symbol for the application and wire size Do not reduce wire size to fit connector by cutting off strands Use proper size connector After insulation has been stripped from the aluminum conductor coat the conductor end with corrosion inhibitor Burndy Penetrox A or equivalent and wire brush the aluminum surface thru the inhibitor After cleaning recoat the aluminum conductor with inhibitor and make connection then coat entire con nection If applicable wrap the connection for moisture and or electrical protection Filters The filters are factory installed in the bottom of the furnace This is for bottom inlet application See Figure 5 DURALAST ALTER FILTER amp f RETAINER SP A73115 Figure 5 Filter Installed For Bottom Inlet For side inlet application see Figure 2 and Table I for the opening size Remove the filter and the retainer spring from the bottom opening Install the retainer spring
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