Our furnace is 16 years old and we live in an older home.
For the past two days our furnace starts to heat, the fan starts and then a few seconds later the fan shuts off and the burner continues to run and it continues this short cycle. We have had two different technicians come in. The first one replaced the fan/limit switch and that made it a lot worse. Then someone came back and a made some adjustments to the switch but it still runs a short cycle.
We added two returns upstairs in the fall. Is there anyway that this has something to do with the short cycle and is it really possible that the air is so cold that it is drawing in that it would shorten the cycle so much? It didn't do this last year and it was just as cold.
Does anyone have any thoughts on this? (I apologize if I didn't describe this too well, heating systems are not my speciality :) I will be more than happy to answer clarifying questions if I can.
Thank you, I really appreciate it.