White Rodgers 50A55-143 User's Manual
Contents
1. Hs 24 VAC CLASS II le TRANSFORMER COOL HEAT CIRCULATOR BLOWER LINE XFMR EAC IND Mien IGNITOR XFMR N h EAC N LINE N XFMR N ELECTRONIC EAC N AIR CLEANER COMPRESSOR CONTACTOR 50A55 143 IN OTHER FURNACES TWINNING THERMOSTAT APPLICATIONS ONLY PRESSURE SWITCH N O OO OO HIGH LIMIT AUX HIGH N C LIMIT N C ROLLOUT N C LEGEND Low Voltage 24 VAC Line Voltage 120 VAC N C Normally closed switch N O Normally open switch TYPICAL SYSTEM WIRING TABLE TERMINAL TYPE CONNECTION low voltage thermostat W terminal or equivalent Terminal low voltage thermostat G terminal or equivalent block with low voltage thermostat R terminal or equivalent captive low voltage thermostat Y terminal or equivalent screws 2nd wire from Y terminal goes to 24 VAC HOT side of compressor contactor coil one wire twinning terminal 24 VAC COMMON side of compressor contactor coil MV 2 terminals gas valve both gas solenoids are connected in parallel TR 24 VAC transformer low voltage COMMON side TH 24 VAC transformer low voltage HIGH side rollout switch OUTPUT 12 pin rollout switch INPUT connector flame sensor probe amp harness pressure switch INPUT high limit INPUT high limit OUTPUT MUST BE RELIABLY GROUNDED TO CHASSIS FP PS HLI HLO GND 2 pin inducer HOT side connector unused terminal IND IGN amp harness ignitor HOT side hum2. This control is a precision instrument and should be handled carefully Rough handling or distorting compo nents could cause the control to malfunction CONTENTS Description Precautions Specifications Installation Mounting amp Wiring Operation ENS WH TE RODGERS DIVISION Em EMERSON ELECTRIC CO ce 9797 REAVIS ROAD EMiERsON ST LOUIS MISSOURI 63123 5398 DESCRIPTION To prevent electrical shock and or equipment damage disconnect electric power to system at main fuse or circuit breaker box until installation is complete Label all wires prior to disconnection when ser vicing controls Wiring errors can cause im proper and dangerous operation This control is not intended for use in locations where it may come in contact with water Suit able protection must be provided to shield the control from exposure to water dripping spray ing rain etc Do not use on circuits exceeding specified volt age Higher voltage will damage control and could cause shock or fire hazard Do not short out terminals on gas valve or pri mary controlto test Short or incorrect wiring will damage thermostat and could cause personal injury and or property damage PART NO 37 6095A Printed in U S A 9919 SPECIFICATIONS ELECTRICAL RATINGS 77 F 25 C Input Voltage 25 VAC 50 60 Hz Max Input Current 25 VAC 0 45 amp Relay Load Ratings Valve Relay 1 5 amp 25 VAC 50 60 Hz 0 6 pf Ignitor Relay 6 0
3. orthe fault condition is corrected before the last ignition attempt Otherwise the control will go into system lockout If the control has gone into system lockout it may be possible to reset the control by a momentary power interruption of one second or longer Refer to SYSTEM LOCKOUT FEATURES COOL MODE In atypical system a call for cool is initiated by closing the thermostat contacts This energizes the 50A55 control and the compressor The cool delay to fan on period begins After the delay period ends the optional elec tronic air cleaner is energized and the circulator fan is energized at cool speed After the thermostat is satisfied the compressor is de energized and the cool mode delay to fan off period begins After the delay to fan off period ends the circulator fan and electronic air cleaner op tional are de energized MANUAL FAN ON MODE If the thermostat fan switch is moved to the ON position the circulator fan cool speed and optional electronic air cleaner are energized When the fan switch is returned to the AUTO position the circulator fan and electronic air cleaner optional are de energized TWINNING INTERFACE If the control has six screw terminals one of which is designated TWIN the control is equipped with a single wire twinning interface If twinning is used either control will process acall for heat cool or fan as described above However after the heat cool or fan on delay time expir
4. the ignitor on time will continue until flame fails to be achieved resulting in a retry In the event of a retry the warm up time will be increased by two seconds and locked in at that duration Once the warm up time is locked it remains fixed until another call for heat results in a retry in which case the warm up time is again increased by two seconds and remains locked In the event of two successive retry attempts the warm up time will be unlocked and set to 21 seconds If flame is then achieved the warm up time will begin adapting again with the next call for heat If however this third attempt fails to achieve flame the control will go into system lockout At the end of the ignitor warm up time both valves in the 36E manifold gas valve are opened Flame must be detected within 4 seconds If flame is detected the delay to fan on period begins After the delay to fan on period ends the optional elec tronic air cleaner is energized and the circulator fan is energized at heat speed When the thermostat is satis fied the gas valve is de energized After proof of flame loss the heat delay to fan off period begins and the inducer blower remains energized to purge the system for 5 seconds When the purge is complete the inducer blower and humidifier are de energized After the delay to fan off period ends the circulator fan and electronic air cleaner are de energized If flame is not detected both valves are de energiz
5. WHITE RODGERS 50A55 143 Integrated Furnace Control INSTALLATION INSTRUCTIONS Operator Save these instructions for future use FAILURE TO READ AND FOLLOW ALL INSTRUCTIONS CAREFULLY BEFORE INSTALLING OR OPERATING THIS CONTROL COULD CAUSE PERSONAL INJURY AND OR PROPERTY DAMAGE The 50A55 143 is an automatic gas interrupted ignition control that employs a microprocessor to continually monitor analyze and control the proper operation of the gas burner inducer and fan Signals interpreted during continual surveillance of the thermostat and flame sensing element initiate automatic ignition of the burner sensing of the flame and system shut off during normal operation These controls incorporate system fault analysis for quick gas flow shut off coupled with automatic ignition retry upon sensing a fault correction J Y GENERAL PRECAUTION Application of this type of control may cause flame rollout on initial start up and could cause personal injury and or property damage Replace only with exact model number includ ing dash number Failure to use exact replace ment control could cause personal injury and or property damage If in doubt about whether your wiring is millivolt line or low voltage have it inspected by a qualified heating and air conditioning contractor or licensed electrician Do not exceed the specification ratings All wiring must conform to local and national electrical codes and ordinances
6. amp 120 VAC 50 60 Hz resistive Inducer Relay 2 2 FLA 3 5 LRA 120 VAC Circulator Relay 14 5 FLA 25 0 LRA 120 VAC Flame Current Requirements Minimum current to insure flame detection 1 ua DC Maximum current for non detection 0 1 wa DC Maximum allowable leakage resistance 100 M ohms Measured with a DC microammeter in the flame probe lead OPERATING TEMPERATURE RANGE 40 to 175 F 40 to 80 C HUMIDITY RANGE 5 to 93 relative humidity non condensing MOUNTING Surface mount multipoise Timing Specs 60 Hz maximum Flame Establishing Time 0 8 sec Flame Failure Response Time 2 0 sec At 50 Hz all timing specifications should be increased by 20 Gases Approved Natural Manufactured Mixed Liquified Petroleum and LP Gas Air Mixtures are all approved for use TIMING SPECIFICATIONS All times are in seconds unless noted otherwise 50A55 143 PRE PURGE INITIAL IGNITOR WARM UP 1st 64 attempts MINIMUM IGNITOR WARM UP MAXIMUM IGNITOR 21 WARM UP IGNITION ACTIVATION PERIOD TRIAL FOR IGNITION PERIOD VALVE SEQUENCE PERIOD INTERPURGE 8 POST PURGE LOCKOUT TIME 15 30 DELAY TO HEAT ON 45 60 60 90 DELAY TO HEAT OFF 120 180 DELAYTOCOOLON o EE wh DELAY TO COOL OFF AUTO RESET HUMIDIFIER ELECTRONIC AIR MOUNTING AND WIRING Do not use on circuits exceeding specified voltage Higher voltage will damage control and could cause
7. ed the ignitor is turned off and the 50A55 control goes into the retry sequence The retry sequence provides a 60 second wait following an unsuccessful ignition attempt flame not detected After this wait the ignition sequence is restarted with an additional 2 seconds of ignitor warm up time If this ignition attempt is unsuccessful one more retry will be made before the control goes into system lockout If flame is detected then lost the 50A55 control will repeat the initial ignition sequence for a total of four recycles After four unsuccessful recycle attempts the control will go into system lockout If flame is established for more than 10 seconds after ignition the 50A55 controller will clear the ignition attempt or retry counter If flame is lost after 10 seconds it will restart the ignition sequence This can occur a maximum of five times before system lockout During burner operation a momentary loss of power of 50 milliseconds or longer will de energize the main gas valve When power is restored the gas valve will remain de energized and a restart of the ignition sequence will begin immediately A momentary loss of gas supply flame blowout or a shorted or open condition in the flame probe circuit will be sensed within 2 0 seconds The gas valve will de ener gize and the control will restart the ignition sequence Recycles will begin and the burner will operate normally ifthe gas supply returns
8. es both units will energize the circulator blowers at the same time Likewise after the heat cool or fan off delay time expires both units will de energize the circula tor blowers atthe same time This allows for proper airflow to be obtained To assure proper control operation both controls must share a common transformer ground TR To enable twinning do the following 1 Power supplied to both furnaces must be from the same phase of the incoming 120 VAC power 2 Connectthe TWIN screw terminals on the 50A55 143 of the furnaces to be twinned to each other using a single wire 14 22 AWG SYSTEM LOCKOUT AND DIAGNOSTIC FEATURES SYSTEM LOCKOUT FEATURES When system lockout occurs the gas valve is de ener gized the circulator blower is energized at heat speed and if flame is sensed the inducer blower is energized The diagnostic indicator light will flash or glow continu ously to indicate system status System lockout will never override the precautionary features To reset the control after system lockout do one of the following 1 Interrupt the call for heat or cool at the thermostat for atleast one second but less than 20 seconds if flame is sensed with the gas valve de energized interrupt ing the call for heat atthe thermostat will not reset the control 2 Interrupt the 24 VAC power at the control for at least one second You may also need to reset the flame rollout sensor switch 3 Afteronehouri
9. idifier HOT side circulator blower NEUTRAL terminal input voltage 120 VAC NEUTRAL side HUM N optional Spade terminal humidifier NEUTRAL side maximum recommended flame probe wire length is 36 inches OPERATION OPTION SWITCHES The option switches on the 50A55 143 control are used to determine the length of the heat delay to fan off periods The following table shows the time periods that will result from the various switch positions OPTION SWITCH POSITIONS HEAT delay Set switch to fan on 1 2 HEAT delay Set switch to fan off 3 4 60 sec 90 sec 120 sec 180 sec HEAT MODE In atypical system a call for heat is initiated by closing the thermostat contacts This starts the 50A55 control s heat ing sequence The inducer blower and optional humidifier are energized and after the 30 second prepurge the ignitor is powered within one second This controller has an adaptive algorithm that adjusts the duration of the ignitor warm up to extend ignitor life Upon initial application of power the warm up time is 17 sec onds The ignitor on time will then be increased or de creased depending on whether or not flame is achieved The warm up time is limited to a maximum of 21 seconds During the first 64 warm up periods following power up the warm up time may not be less than 17 seconds Upon a call for heat if the warm up time has not been locked it will be decreased by one second This reduction of
10. instruction sheet and apply it to the mounting location When drilling the holes take care so that the transformer wiring har ness or other system components are not damaged Four 4 8 sheet metal screws are provided to complete the installation Refer to the wiring diagram and wiring table when con necting the 50A55 control to other components of the system UL approved 105 C rated 18 gauge stranded 4 thick insulation wire is recommended for all low voltage safety circuit connections Refer to 50A55 specification sheet for recommended terminals to mate with those on the control UL approved 105 C rated 16 gauge min stranded 4 thick insulation wire is recommended for all line voltage connections Refer to 50A55 specification sheet for rec ommended terminals to mate with those on the control After installation or replacement follow appliance manufacturer s recommended installation or service in structions to ensure proper operation The 50A55 has only one serviceable part an automotive type fuse which protects the low voltage transformer from damage if its output is short circuited If the fuse has opened up remove whatever caused the short circuit and replace the fuse with only a 3 Amp automotive type fuse If the fuse is not the cause of the control s problem replace the entire 50A55 control There are no other user serviceable parts TYPICAL SYSTEM WIRING DIAGRAM HOT NEUTRAL LINE LINE 120 VAC
11. nlockout the control will automatically reset itself DIAGNOSTIC FEATURES The 50A55 control continuously monitors its own opera tion and the operation of the system If a failure occurs the LED will indicate a failure code as shown below If the failure is internal to the control the light will stay on continuously In this case the entire control should be replaced as the control is not field repairable If the sensed failure is in the system external to the control the LED will flash in the following flash pause sequences to indicate failure status each flash will last approximately 0 25 seconds and each pause will last approximately 2 seconds 1 flash then pause 2 flashes then pause 3 flashes then pause 4 flashes then pause 5 flashes then pause 6 flashes then pause System lockout Pressure switch stuck closed Pressure switch stuck open Open limit switch Open rollout switch 115 Volt AC power reversed improper ground Low flame sense signal Flame has been sensed when no flame should be present no call for heat The LED will also flash once at power up 7 flashes then pause Continuous flashing no pause MOUNTING HOLE TEMPLATE FOR MOUNTING HOLE LOCATIONS 4 172 007 2 ples 6 402 010 2 ples Refer to page 3 of the installation instructions for proper installation
12. shock or fire hazard To prevent electrical shock and or equipment damage disconnect electric power to system at main fuse or circuit breaker box until installation is complete Failure to earth ground the appli ance or reversing the neutral and hot wire con nection to the line can cause shock hazard Shut off main gas to heating system until instal lation is complete Route and secure all wiring as far from flame as practical to prevent fire and or equipment damage To prevent damage to the transformer system components or wiring harness take care when drilling new mounting holes Failure to do somay result in electrical shock fire hazard or equip ment damage INSTALLATION All wiring should be installed according to local and national electrical codes and ordinances The control must be secured to an area that will experi ence a minimum of vibration and remain below the maxi mum ambient temperature rating of 175 F The control is approved for minimum ambient temperatures of 40 F When mounting the control any orientation is acceptable Choose a location that will not damage obstruct or place stress on the control s terminations system wiring har ness or system components After finding a suitable location drill four 4 7 holes for mounting control To ensure proper mounting hole locations there is a mount ing hole template on page 8 of this instruction sheet Detach the page with the template from the
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