HELP with furnace in Wheatridge!!!

[Wulf202]

I just put back the old pressure switch and it fired up.
Will probably work for a few days and then we'll have issues again...
I guess the board is the next thing?
Hopefully I can return the switch and put it toward a control board.

You're just throwing parts at it. Trouble shoot it by looking up the code first off.

[Wulf202]

Audible click followed by the fan
It then will check the pressure switch.

Audible click. Flame igniter will heat up or spark igniter. Either orange glow or a bug zapper sound

Audible click. Gas valve turns on.

Hear the ignition of the gas. See a blue glow

It then checks with the flame sensor to make sure it's not dumping pure gas into the house.

Which step do you get to?

Ace in Aurora off iliff usually sells hvac parts.

[Wulf202]

I have already cleaned it .....
Regardless, once it's cleaned, it is just a piece of metal, not much can go wrong there.

That wire goes to important bits inside the metal. That can go bad.

[Wulf202]

I just put back the old pressure switch and it fired up.
Will probably work for a few days and then we'll have issues again...
I guess the board is the next thing?
Hopefully I can return the switch and put it toward a control board.

The line to the pressure switch goes to the fan. Inside that little barbed fitting can gather debris. Clean it with a paper clip. Then blast it with canned air if you have it.

Check the hose for pin holes plug one end and blow on it. You can also cycle the pressure switch and check its continuity.

[bellavite1]

Did the continuity test on the pressure switch, all good.
Cleaned the hole in the fan already as well.
Managed to find the error code, pointing to the thermostat.
I already replaced the old thermostat with one i had laying around (never used), and did not make a difference, would work for a few days and then crap out.
I assume i could have ywo bad thermostats, I guess.
Ill go buy a third one tomorrow and if nothing else I should be able to return it if it doesn't fix things ...

[Wulf202]

Managed to find the error code, pointing to the thermostat.

That's.... unusual. Like I've rarely seen a board in a home furnace that can diagnose a tstat issue. And the ones I've seen than can, the HVAC system is worth more than many vehicles are.

What brand of furnace? If it's a Coleman 8 flashes does not mean a thermostat issue. It just means its cycles too many times and locked out

Goodman 8 flashes means no ignition detected. Could be ignitor or flame sensor


After re reading a couple of times. Your description of the symptoms seems to be the flame sensor.

[fitterjohn]

I have already cleaned it
I went to a place to get my pressure switch today and they wanted $60 for a flame sensor.
That's because most places don't sell retail, only wholesale to HVAC companies.
Regardless, once it's cleaned, it is just a piece of metal, not much can go wrong there.
Any of our members in the trade at all?

Even if you cleaned it you need to make sure it?s positioned correctly and that it does not have a crack in the porcelain. I have diagnosed that before when they have a hairline crack in them.

[eddiememphis]

What brand furnace? Make model and serial number.

A flame sensor is not just a piece of metal. Some of them have a bi-metal switch in it that allows the furnace to run. Cleaning it does nothing.

[Jamnanc]

Had the same issue. Burned for three seconds, flared out. Flame sensor needed scrubbing.

[ray1970]

Likely the flame sensor. I have to clean mine a couple of times every season. I clean mine with some 320 grit emery paper.

Also, depending on your thermostat, if it has a battery or batteries inside and you can?t remember the last time you replaced them it might be worth putting new batteries in. I was having weird issues once and although everything looked okay on the display apparently the batteries were weak enough that the thermostat just couldn?t perform properly.