WARNING WARNING TROUBLESHOOTING GUIDE INTEGRATED FURNACE CONTROL MODULE

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Carol Armstrong
6 years ago
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TROUBLESHOOTING INTEGRATED FURNACE Failure to read and follow all instructions carefully before installing or operating this control, could cause personal injury and/ or property damage.

1 TROUBLESHOOTING INTEGRATED FURNACE Failure to read and follow all instructions carefully before installing or operating this control, could cause personal injury and/ or property damage. 50A55 INTEGRATED FURNACE Qualified Serviceman s Troubleshooting Guide TROUBLESHOOTING PROCEDURE If the light on the module is on continuously, the fault is likely to be internal to the module. To make sure, interrupt line or 24 volt thermostat power for a few seconds and then restore. If internal fault is indicated again, and flame sensor is not shorted to ground, replace control. A flashing light indicates the problem is most likely in the external components or wiring. Proceed as follows: Turn power off before any troubleshooting or servicing begins. Line voltage (120 VAC) could be present on the surface of the ignitor, if the system is not correctly wired. Such voltage can cause serious injury or death. The following steps must be performed first before any troubleshooting begins. 1) Disconnect electric power to system at main fuse or circuit breaker. 2) Visually inspect equipment for apparent damage. wiring for loose connections. 3) for proper grounding and reversed polarity. A. continuity for C terminal on module to electrical service ground and connection at the furnace junction box. If ground connection is open, check module ground connection and the electrical service ground connection. Repair and retest. B. Re-connect electric power to system. C. for voltage between the line neutral terminal and furnace ground. If voltage exists, the main power supply lines are improperly connected to the furnace (REVERSED POLARITY). Again disconnect electric power to system; then reverse incoming supply leads to furnace. Repeat step. D. Recheck system for proper If neither apparent damage, loose connection nor reversed polarity is the problem, proceed to troubleshooting chart or fault index chart that is suggested by the actual condition. TE: This troubleshooting guide is not for 50A55-4XX modules found on Trane equipment or 50A55-1XX modules found on Lennox equipment. FAULT INDEX CHART No manual fan... 1A - 1K Power supply and voltage... 1C - 1G No fan at cooling speed... 2A - 2L No induced draft motor... 3A - 3H LED flashing 2X without inducer... 3E LED flashing 3X with inducer... 3I - 3O Ignitor does not glow... 4A - 4D Burner does not stay lit... 4E - 4N Gas supply problem... 4F - 4K No outlet... 4H - 4J Gas valve does not energize... 4L - 4N Flame sensor fault... 5A - 5P Burner ground... 5K Polarity check... 5L - 5M Ignitor stays on after burner ignition... 5B - 5C 259

INTEGRATED FURNACE TROUBLESHOOTING CHART 1 1A 1B Indoor Blower Place thermostat fan switch in the ON position. Does indoor blower run at HEAT speed? Return fan switch to AUTO position.

2 INTEGRATED FURNACE TROUBLESHOOTING CHART 1 1A 1B Indoor Blower Place thermostat fan switch in the ON position. Does indoor blower run at HEAT speed? Return fan switch to AUTO position. 1C Does LED flash 1 time when disconnect is turned ON? 1D control terminals R & C? 1E control terminals G & C? 1F COOL & CIR Indoor blower fault. Repair or replace. from control to thermostat. 1G 1H 1I 1J 1K LINE & LINE XFMR & XFMR primary of control transformer? secondary of transformer? present across 12-pin connector pins TH & TR on the control? Correct 120V power supply. disconnecting electrical power to transformer. Replace transformer. and/or plug connection

3 TROUBLESHOOTING INTEGRATED FURNACE CHART 2 Cooling Cycle Place thermostat system switch in cooling mode and fan switch in AUTO position. Lower temperature selection lever to call for a cooling cycle. R & Y contacts close. 2A Does indoor blower energize at cooling fan speed? 2B Return thermostat to desired setting. 2C 2D 2E 2F Does indoor blower energize at heating fan speed? thermostat terminal Y connected to furnace terminal Y? With door switch closed, jumper control terminals R & Y. Does indoor blower energize at cooling fan speed? Repair low voltage wiring to thermostat. 2H Correct wiring from thermostat terminal Y to Y on furnace. COOL & CIR Indoor blower fault. Repair or replace motor. 2G Y & C? 2I 2J 2K R & C? G & C? present at primary of transformer? Replace transformer. 2L Repair low voltage wiring to thermostat. Repair low voltage wiring from transformer to control. LINE & LINE Correct 120V power supply to control. between control and transformer primary. disconnecting electrical power 261

4 INTEGRATED FURNACE TROUBLESHOOTING CHART 3 3A 3F Inducer Draft Motor and Pressure Switch Call for heat. Thermostat contacts R & W close. induced draft motor energized? diagnostic LED flashing 3 times? 3B 3G diagnostic LED flashing 2 times? Jumper switch. 3C 3H Disconnect electric power at fuse or circuit breaker. Does ignitor glow? 3D 3I Test for continuity across switch. Place incline manometer in series with switch tubing. 3E 3J inducer wiring. If OK, repair or replace inducer motor. switch welded closed? greater than switch specs? Replace switch. 3K Replace switch. Energize system. Remove vent connector from furnace flue collar. 3L disconnecting electrical power greater than switch specs? Repair leaks in inducer assembly or replace induced draft motor. Correct blocked or incorrectly installed vent

5 TROUBLESHOOTING INTEGRATED FURNACE CHART 4 4A 4E Main Burner Ignition. Inducer ON. Does ignitor warm up and glow? Does burner ignite? 4B Turn power OFF to furnace. Unplug ignitor from wire harness. Connect voltmeter across ignitor wiring harness leads from control. Energize system. 4F gas valve manual knob in ON position? Turn manual knob to ON position. 4G Turn manual knob to OFF position. Connect manometer to outlet tap. Turn knob to ON position. Energize system. Purge system of air. Energize system. 4C 4H 4I 4J Replace ignitor. ignitor leads? outlet detected after ignitor warmup time? Refer to service facts or installer s guide for proper settings. manifold adjusted to required setting? 4K gas at source? Adjust manifold to required setting. 4D 4L Replace broken or defective wiring. IGN & IGN Connect voltmeter to gas valve leads. Energize system. Restore gas supply at source. 4M detected across gas valve leads after ignitor warmup time? 4N present across control MV terminals after ignitor warmup time? Replace control module. Replace gas valve. Energize system. Repair or replace broken leads to gas valve. disconnecting electrical power 263

6 INTEGRATED FURNACE TROUBLESHOOTING CHART 5 5A 5B 5C Flame Sensor Does main burner remain lit? Does ignitor remain energized with flame present? blower at heat speed within 1 minute of burner ignition? System is functioning properly. 5E De-energize system. Disconnect 12-pin connector. Connect ohmmeter from flame sensor pin FP to burner GROUND. 5D HEAT & CIR and/or replace indoor blower motor. Replace control module. 5F resistance less than 50 megohms (50,000,000 Ohms)? 5I Disconnect flame sensor from wire. Measure continuity from wire end to FP pin on 12-pin connector. 5L Disconnect AC power to system at main fuse or circuit breaker. Connect voltmeter from control terminal LINE NEUTRAL to BURNER GROUND. Energize module. 5M burner ground? Reverse 120V LINE & NEUTRAL wires. Energize system. 5G Disconnect lead from flame sensor. Connect ohmmeter from sensor to burner ground. 5J sensor lead good? 5K control ground wire connected to burner ground? 5N Connect a microammeter in series with flame sensor and sensor lead. Energize system. Measure current when burner ignites. Clean surface of flame sensor with fine steel wool. Reinstall. 5H Repair or replace wire. Energize system. Connect ground wire from burner to 12-pin connector terminal GROUND. 5O 1 microamp or more present? 5P Remove sensor. Does sensor have carbon or dust buildup? resistance less than 50 megohms? Replace sensor. Energize system. Replace flame sensor lead. disconnecting electrical power 264

50A Integrated Furnace Control

50A Integrated Furnace Control Goodman White-Rodgers 0130F00005 PCBBF110 PCBBF123 50A55-743 0130F00005S PCBBF110S PCBBF123S 50A55-289 B1809926 PCBBF112 50T55-289 B1809926S PCBBF112S 50A55-743 Integrated Furnace Control INSTALLATION