I’ve been using this unit on a radiant tube in my shop for 10 years now with very few issues till now. The controller is set for 4 minute post time but runs only 15 seconds then shuts off. I’ve tried reprogramming the controller with a Genisys contractors tool to 4 minutes but still only runs 15 seconds. This has happened a few years back but seemed to correct itself. Is the controller faulty ?

I don't know a lot about furnaces. We have a gas furnace and the heat keeps going out. The furnace is still of, it's just not blowing anything warm and the flame isn't on. The thermostat is set to auto at 72 but right now it's 67. Sometimes it will start working again, especially if I turn it off for a minute and back on. The last time, I had someone come look at it and all they did was clean it and that worked. That was two years ago. I looked at the service sticker that shows when it was last serviced and it was a good number of years before that. This is the first home I've owned. I've owned it for 7 years but there are still things I come across that I realize I should be maintaining regularly. I don't know if it just needs to be cleaned again but I assume so. I'm pretty handy but I don't want to go poking around something I am unfamiliar with when fire is involved. Any suggestions? Does it just need to be cleaned? If so, how and how often?