Thanks for giving me the opportunity to help! Make and model number of furnace? Are you getting a LED diagnostic code?
No. Display just shows HLD 53 degrees, even though I tried to set it at HLD 71. Arrow is also pointing to SYSTEM ON.
Make and model number of furnace? Are you getting a LED diagnostic code?
Frigidaire heating & cooling unit. Model C38A 036A. I don't think the thermostat has an LED diagnostic code.
The LED code would be on the furnace, most likely on a lower door and inside a small window.
I will check for it now. Be back shortly.
There's a sticker above the condenser pump with the following: FG6RA 072C 12 A. I also took the door off the furnace. The door has a status red light column. The red light in the furnace is flashing once periodically, which lists limit circuit open or external load on W as the fault condition. There are also operating instructions to turn off the gas to the appliance. This unit does not have a pilot.
Do you have blower if you turn thermostat to fan "on" position?
Yes, and now it is blowing cold air.
You most likely have an open limit switch, then
What does that mean?
It means one of the limits, either the main or flame rollout switch is open.
I can't bring up anything with that model number you gave me.
I have the wiring diagram for the furnace. It says it's for 78+ 80+, 90+ & 93+ model furnaces. Does that help? Should I try turning the furnace off and then on again?
Flame rollout switch should look like this
I will see if I can find this switch on my furnace. Should I try to close it?
Yes, it has a reset button
The high limit, if it's open is not resettable. It should reset by itself, otherwise replace.
OK. I will try to find it. Also, I did see a narrow red lever outside the furnace. It kind of looks like a pilot light.
I will be right back.
I didn't find the flame rollout switch, but I found the model number: FGRA 072C 12A. I also found what looks like a black arrow on a circle that was pointing to ON. I can switch it down to OFF. Don't know if that does anything.
I don't know what that would be... We are talking about a Frigidaire forced air furnace, right?
There should be a high limit switch right above the burners.
How old is this furnace?
I think it's about 8-10 years old. Also the operating instructions on the door say that the unit does not have a pilot, but it has an ignition device which automatically lights the burner.
Sorry, hit the reply key too soon
Here are some high limit controls. Any look like yours?
May also look like this.
The operating instructions also say that the black knob is the gas control knob. It says to turn it off for five minutes, then on. I am going to try that and also look for the high limit controls. Be back shortly...hopefully!
OK. This may take a while so I'll switch to Q and A mode. You can still post questions.