My friends’ central heat is out. It is one of those combo a/c/heat units. Here is what happens. The thermostat turns an electic element on, which ignites two long tubes, presumably filled with gas, that create the fire that heats the air. The problem happens a couple of seconds after the tubes are ignited…they get switched off. The ‘clicking’ sound that turns the fire off is coming from a little square white box from Emerson Electic with about 7 different colored wires plugged into it. Does anyone know how to fix this? I’d really hate to pay a couple hundred bucks if it is as simple as replacing a wire or that control module…
Take that box off or get the numbers off of it. Go to a Heating and A/C supply store and ask them. If they think you shouldn’t do it yourself they will tell you.
This happened to me a year ago. The heater just stopped working. Sometimes I could get a flame going, but it would quit without warning.
I took the panel off the furnace and discovered a wiring diagram and instructions on how to test the furnace - you short out two contacts and turn the power on, and it cycles through testing all the parts. They all tested OK, but it was still broken.
Called the furnace guys, and they replaced the computer control unit. $800.
An entirely new furnace costs somewhere in the $2500-$3000 range, I’m given to understand. Pathetic.
I guess my point is if it is an older unit you may be able to make some sense of it, but a newer one may have a completely computer controlled brain and you are out of luck if that thing is shot.
Well I went to furnaceparts.com and found the white box that is making the clicking noise - it is a “hot surface ignition control.” $81.00, all sales final. As an amateur, I’d say that it is the suspect part. Is there any other part to check before dumping the $81?
The control unit has a little red diagnostic LED that checks out as okay. Now I think the unit is using its’ “lockout” function…why would it do that, assuming it is working properly?
Y’know, my Aged Mother had a similar problem with her furnace (gas-fired forced air) and the problem was a restriction in the flue. The chimney wasn’t drawing properly, due to corrosion and collapse of the chimney liner, and the brain box was shutting the furnace down as a safety measure. She hired a furnace guy who removed the corroded liner (told her that since her chimney was ceramic-lined, she’d never needed one anyway) and everything was hunky-dory.
Go look up your flue.
I don’t know where you are seth, but Im in California & when something like that happens I call the gas comp, they come out & look at it for free. Often they correct things for free for me, too.
Hmmm… our furnace (boiler, actually) has a CO monitor built into the unit, and it also has an automatic damper that closes and opens the flue. If the CO monitor reads high, or the flue damper doesn’t open, the boiler will automatically shut off. Check where all those colored wires end up and you might find the responsible part, and you can troubleshoot from there.
Warning, though. IF you have a CO sensor that’s shutting off the system, you better find out WHY rather than try to bypass it.
My friend is in Valencia, CA (north of LA). Do you just call the main number for help?
This sounds like a fairly new unit. It may have a “window” with an LED which is blinking. I will blink (e.g., 2 times), pause and blink again (e.g., 3 times), longer pause, and start over.
On the inside cover of the removable panel will be a legend of troubleshooting codes (2-digit numbers). The first blinking series is the first number. The blinking series after the short pause id the second number. So if the blinking series indicate 23, as in my example, that number should be explained in the legend.
Does this unit have a regular chimney or is it a direct vent?
A direct vent unit has an intake pipe to draw air into the combustion chamber from outside. A leaf may have been sucked in and is partially blocking the combustion air. The troubleshooting code should indicate if this may be one of the causes of your symptom.
The house was built in 1993, so it is pretty new. It is a direct vent (it’s in the garage). The white box with the LED on it doesn’t have any of the codes you are talking about. It says if the light blinks or stays on something is wrong. The light does neither.
I call the PGE nbr on the statement. Then explain the situation. One time they came out within about an hour…but that was a more dangerous situation.