So full disclosure, I am an HVAC service tech. 6 years experience but always learning. My mom's trane natural gas furnace goes out. Getting error code that says out on retries. System cycles through its normal startup procedure, and gets to where the ignitor glows, control board clicks to send power to gas valve. Nothing happens. I disconnect the 2 leads and when disconnected, I have 27 volts across when the control board is energizing the gas valve. Ok, bad gas valve. I order new gas valve and replace. Same thing happens. I think, ok maybe bad gas valve from the factory, and order new one. You guessed it, same thing happens.

I got smart and disconnected the solenoid on the humidifier and put that 24 volts acrossed the gas valve and it opens. I also checked the burners, and orifices/tube that runs from valve to the burners, and there are no obstructions. Anyone have any ideas? Will be calling tech support tomorrow if I can't figure it out.

Question from user Candid_Sand at hvacadvice at reddit.com.

Answer:

Are you smelling gas when it opens? Did you hook a manometer up to see if any gas is actually coming through?

Answer from user EyeSeekYou at hvacadvice at reddit.com.

natural gas furnace help