Chosen Solution
Trying to get my American Standard (Trane) Freedom 90 furnace on and running but having issues. When I turn it on it will go through the normal cycle and after 1 or 2 retries it does light (it is a gas furnace) and it will then stay lit and heat the house. However once it reaches the temperature set on the thermostat and it goes into a like down cycle it does not relight or ignite. I replaced the flame sensor, ignition, and control board, last year and its a new filter. What else can I do to get the furnace to stay lit?
The furnace issue was resolved by cleaning out the condensate drain line which was clogged. Also, there was a couple dead mice in the combustion chamber area that may have prevented all of them lighting up and the flame sensor couldn’t read seeing the last burner wasn’t lighting.
I have run into what appears to be a common problem with furnaces. My son the AC man couldn’t figure it out, but I found it. Then he brought me another from a client. The control board in the unit has a Molex type connector on it. It does not get enough solder during mfg and eventually the solder cracks on the pins and connection is lost. Many times it is temporary until it isn’t. Disconnect power. Take a picture of the board and its connections. Remove the board. Carefully remove the conformal coating from around the connector pins and resolder all the pins with more solder. If you want to get a mag glass and try to see the cracked connection first, do it. It will be hard to see. Replace the board. If that is the problem, it will now run forever.
