Cycling Comfortmaker NTG3075fbg1

Old 11-20-21, 09:13 AM
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Cycling Comfortmaker NTG3075fbg1

My furnace wants to cycle on occasion, I have been chasing this for a couple weeks now. Yesterday's operation was fine, today not so much. Thermostat calls for heat ignitor heats up flames start next then the blower starts.

When it doesn't behave: It will run this above process and few minutes in the process the flame will kick out I can hear the gas valve click on and off while the ignitor try's to reengage, the gas valve continually click on and off continually it sometimes recovers and completes normally other times it starts and endless repeat of the above symptoms. It has never shut down as a result of this it will just keep blowing air and clicking the gas pilot on/off. which make me feel this is not a heat limit switch issue.

I have replaced the flame sensor pilot assembly and thermostat so far and at this point I am considering the control board. In a stroke of genius this summer my neighbors AC had a leak and he elected to replace everything for 9k I asked him if i could have his old furnace and he gave it to me because It is the exact same furnace as mine so I have every part needed at my disposal which honestly looks better than my unit and had no other issues other than the Freon leak.

Hose hitting pressure switch is soft and pliable combustion blower operates normally, filter is and has been clean, I am at a loss at this point other than the control board which for some reason is intimidating me from swapping it out not because it appears difficult and swapping 1 for 1 is simple but what could go wrong and how to handle it. Of course I could be completely incorrect on what this issue is why i will beg forgiveness if so.

Thank you in advance for any suggestions as I am a poor becoming poorer but mechanically inclined retiree
Old 11-20-21, 02:00 PM
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