Carrier furnace
#1
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Carrier furnace
My thermostat controller is completely dead. I checked on the electrical that supply the furnace and is good. Opened up the furnace cover and found out the PCB board unit is CEPL 130438-01. I checked on the AC electrical input to the DC power converter input and no power. I replaced the PCB board and still dead. Is there anything else that may go wrong. Thanks
#2
Welcome to the forums.
That board doesn't run on 120vAC..... it only switches that voltage to the blowers and igniter.
The board runs on 24Vac. Look for a 120vAC to 24vAC transformer. That's what probably is defective.
That board doesn't run on 120vAC..... it only switches that voltage to the blowers and igniter.
The board runs on 24Vac. Look for a 120vAC to 24vAC transformer. That's what probably is defective.
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Yes it's. But I think the 120vAC that run to the DC converter come from the PCBoard and does not have the 120VAC to supply the converter. I assume there is another sensor to give signal a relay to power up the DC converter. thanks
#6
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These boards run the 24vac from the transformer through a limit switch and flame rollout sensor. If either is tripped/broken then the board will act dead like you are seeing.
#10
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What is the model number of your furnace?
Follow the wires. Roll-out switch just above burners. Limit switch can be above or below but is to sense temp in air going through system. Sometimes in blower compartment.
Follow the wires. Roll-out switch just above burners. Limit switch can be above or below but is to sense temp in air going through system. Sometimes in blower compartment.
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I found the limit switches as well . There are two limit swictches on the heat exchange and another one on the flue elbow. Including the Rollout swicth there are 4 sensors chain in a series connection.
#13
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Diagram on page 32 - https://www.questargas.com/ForEmploy...G8M%20PG8J.pdf
First check for 24vac at both sides of the fuse. Then at each of the roll-out sensors and limit switches.
First check for 24vac at both sides of the fuse. Then at each of the roll-out sensors and limit switches.