Furnace not restarting itself.

[ecotec]

My furnace will restart itself if I turn off the single pole switch on the side. The igniter will light up and the gas will start.

Then, it will run, get up to temp… and then just the fan will be running but the gas will be off.

So, it will get the house up to temperature. Then will not start on the next cycle unless I turn the single pole to off and then turn it back on…

It take a while for it to go down a few degrees, so I am not worried about freezing to death. I just don’t want to pay a furnace guy to change out a few parts.

About five years ago, I changed out the blower. About two years ago, I changed out the igniter. They both still work.

I changed out a fuse on my brother in law’s furnace… I have changed out capacitors on a few different AC’s…

I just want to try to fix this myself before I call a furnace guy.

I am an electrician… so I have multimeters and pretty much any tools that an HVAC guy would have.

 

[Bert_]

If it's locking out the circuit board will flash a code telling you why.

I'm going to guess it's a pressure switch code because the condensate drain is plugged

 

[ecotec]

It has two flashes. The schedule on the door says that that means pressure switch stuck closed.

 

[Dakotadadv8]

Not the same issue mine was short cycling I changed the filter. Another time there was a power outage and was unable to restart the furnace, had to reset the flame roll out switch.

 

[dave*99]

If it's locking out the circuit board will flash a code telling you why.

I'm going to guess it's a pressure switch code because the condensate drain is plugged

I just fixed a similar issue. No code, but the draft inducer had water in it and made odd sounds. And the water solenoid valve on the humidifier was clattering on and off. I must have gotten to it just before it was ready to throw a code.

OP---- check the black 5/8" diameter hose coming off the elbow in the lower right corner of your photo.
Could be plugged up.

 

[Bert_]

It has two flashes. The schedule on the door says that that means pressure switch stuck closed.

Means the pressure switch stayed closed after the draft inducer turned off. I would pull the condensate lines off(larger hoses in the corner of the first picture). If a bunch of water comes pouring out you know the lines are plugged.

Pressure switches can go bad, most of the time it's another issue. You can check by sucking on the rubber line going to the pressure switch, it should "click". I did have one recently that "clicked" but did not work when checked with a meter

 

[ecotec]

I just fixed a similar issue. No code, but the draft inducer had water in it and made odd sounds. And the water solenoid valve on the humidifier was clattering on and off. I must have gotten to it just before it was ready to throw a code.

OP---- check the black 5/8" diameter hose coming off the elbow in the lower right corner of your photo.
Could be plugged up.

That was not the code it was throwing… but it was totally plugged up.

I had to text my wife and ask her where in her craft supplies pipe cleaners were… shove it in and grab it from the other end with the really thin jawed needle nose pliers.

It was totally filled with black stuff.

 

[fitter30]

Blocked drain will cause some problems that can can show up as other things. Try it. Hoses going to pressure switch to pull them and blow them out.

 

[dave*99]

That was not the code it was throwing… but it was totally plugged up.

I had to text my wife and ask her where in her craft supplies pipe cleaners were… shove it in and grab it from the other end with the really thin jawed needle nose pliers.

It was totally filled with black stuff.

Mine had pine needles in it that came down the exhaust flue (PVC)

 

[theoldwizard1]

Clean the flame sensor.

 

[ecotec]

Thank you all for your help. I really appreciate it.

 

[dave*99]

Clean the flame sensor.

Um, that wasn’t it.

 

[4x4Pete]

Keep an eye on it. Black in the drain can mean soot. Soot means incomplete combustion. Possible partially blocked secondary heat exchanger. Carrier had a big problem with secondary heat exchanger failures.