First warm, later cool air
From an email:
''Dear Labman,
You seem to give really intelligent answers on the website I just found on heating problems. Can you help me?. here is the problem as I described it. Thanks in advance for any knowledge you might share.
Hoping for help here. I recently had my ignitor replaced. Before that, the furnace wasn't working at all. Now it starts blowing warm (not hot) air, then gradually over a period of a couple of hours, the air cools down until it is completely cold and the temperature in the house drops drastically. The repairman who installed the ignitor advised me to reset a switch on the side of the furnace when this happens... turn it off and then on again. This works as a temporary fix, then in a couple more hours, cold air again. It seems no one is interested in fixing my furnace, only in selling me a new one, although not a single person has been able to tell me exactly what is wrong and how much it would cost to fix it. I don't have any knowledge in this area but I also don't want to spend thousands that I don't have on a new furnace if it's not necessary. Please help! I just want to make a well-informed decision.''
It sounds to me like the flame sensor isn't working right. All it may take is a good cleaning with sandpaper. In order to find and clean it, look at the pictures towards the end of https://www.askmehelpdesk.com/heatin...ons-58313.html
I appreciate the confidence in me you showed by emailing your question, and th ekind words, but site policy is against asking and answering questions by email or a PM. While I am disappointed with the answers some give here, there are others that know more about furnaces than I do. With this posted in the public forum, somebody may give a better answer.
