Have HVAC Questions? Ask an HVAC Expert for Answers
Hi, I'm Tim and I'm an HVAC expert here to assist you with your questions. Please provide all information I request as it makes it more difficult to troubleshoot something when I'm not there onsite. Essentially, you become my eyes and ears. Thanks for the opportunity to help. At the end of our dialog, you will have a chance to rate my service, but please wait until we are finished and you're satisfied you have all the information you need.
This can be caused by a variety of things. If the whole furnace shuts down, it could just be a defective thermostat since the thermostat tells furnace to come on. Do me a favor, next time this happens, before you touch anything, go down to furnace and look in the small window, see if you get an LED flash code, and if so, how many flashes. Also, full model number would be helpful.
No, single flashes doesn't help me. I need to know how many flashes before a pause.
Perhaps I misunderstood you. Are you saying there is a single flash, then a pause, then a single flash, etc?
There is no single flash code according to the manual. Here are the possible flash codes:
There is no single flash code. It will be two flashes and a pause, 3 flashes and a pause, 4 flashes and a pause, etc. Did you open that file I sent you?
Realize, if it's just flashing slow and steady, this is just a call for heat and indicates no error. The flash code I want to see is when the furnace actually shuts down like you said and won't restart. This will indicate an error code. You may have to watch it for a while before this happens.
Again, I sent you a copy of the flash codes. Flashing slow, no call for heat. Flashing fast-call for heat. I don't care about these flashes, this is part of normal operation. What I care about is when unit shuts down when it should be on, that you go down and check it BEFORE YOU TOUCH ANYTHING and tell me what the flash code is, if any. Otherwise, as I said before, could just be a bad thermostat.
Chris, when a furnace has an error code, it will happen when the furnace shuts down when the thermostat is still calling for heat. It will not happen during normal operation. If your furnace actually has an issue, then the furnace will shut down on a call for heat. We don't even know at this point if there is a problem with your furnace. It could be a bad thermostat. That's why the next time that the furnace stops (when it should be on), I want you to go check for a FAULT flash code before you do anything.
Do you have access to a voltmeter?