Furnace advice needed.

[zzvyb6]

So did the transformer change affect the furnace (or not)? If there is a blower motor overheat would there be a code set?

On mine, the intake air got plugged with a cold animal's nest. That caused a computer check and a code was set. Without a code, its going to be guesswork. Can you start the blower manually for full time operation to see if its the problem?

 

[Sigarms]

Without a code, its going to be guesswork.

I've seen numerous occasions where without a dedicated ground circuit for the furnace, you can never rely on what a self diagnostic board is "telling you".

We call them idiot lights at times because if you follow them blindly, you end up replacing parts without figuring out what the actual problem is and may not solve the issue to boot (and some guys do that without the boards help as well). That's not taking into account that sometimes you're getting a "double negative" (think that's the term) that is giving you a misreading on the board to begin with.

1. Check ground to furnace (should be a dedicated ground)
2. Check gas pressure (inlet and outlet)
3. Check standby and running - line/low voltage / check ALL wiring
4. Check tubing and verify rated pressure for pressure switch/switches

Without a decent manometer and clamp meter ("rated" for HVAC use), yes, you're pretty much guessing.

Don't use sand paper to clean the flame sensor rod. Use mild steel wool

+1

My son suggested to check the roof and see if the chimney is covered with snow, it may not be getting the makeup air it requires, I'll look tomorrow.

Unless the furnace is using a two pipe system or some sort of concentric vent kit which most likely isn't the case (because we're assuming you have a standard 80% non variable speed gas furnace being vented on through the chimney by your comment), the chimney would have nothing to do with make up air (air used for combustion), but something could be obstructed in the vent, which could be causing a pressure related issue.

 

[ToadHill]

I took the grandson out with me to the farm today and he got up on the roof with a shovel. He cleared out an area about 5 ft. on all sides of the chimney. It is a pipe within a pipe system. I went inside and started up the furnace and it ran just fine so lack of combustion air must have been the problem.

Thanks everyone for the ideas.

The chimney only is about 24" from the roof and when the snow drifts over the peak it must have covered it up. I guess I'll have to find a piece of pipe to add another 2 ft. on the top so it won't happen again.

 

[tommu56]

what control does it have on it my york and the honey well have an led that blinks a code for fault.
my original youk board died and I put a generic replacement in still blinks a code on board. but you have to take 3 covers off to get to it hold safety switches in and turn on power on then watch led and count the pulses.


That said does the air fan start?
if it doesn't start i would look at the rate of rise limit or high temp limit the a flame detector which is a stainless steel probe in some if its stainless steel some can be cleaned with a stainless steel pad or use a scotch bright pad.

tom

 

[Travelover]

Friend of mine has a high efficiency furnace with the two plastic pipes - inlet and exhaust. He called up the furnace repairman 'cause the furnace won't heat. Repair guy shows up, stomps on his hosta plants growing in front of the pipes, then charges him $100. :laughing:

 

[Steve_Miller]

I took the grandson out with me to the farm today and he got up on the roof with a shovel. He cleared out an area about 5 ft. on all sides of the chimney. It is a pipe within a pipe system. I went inside and started up the furnace and it ran just fine so lack of combustion air must have been the problem.

Thanks everyone for the ideas.

The chimney only is about 24" from the roof and when the snow drifts over the peak it must have covered it up. I guess I'll have to find a piece of pipe to add another 2 ft. on the top so it won't happen again.

If it did have a photoeye and a lack of air it may have been running to rich and smokey causing the eye not to pick up the flame. I remembered after the fact that a couple years back that my furnace (forced air) would run for several minutes and shut down, then restart over and over, after a couple of days I figured out that the air filter in the plenum was plugged to the point that there was not enough air flow causing the plenum temperature to rise to the point that it shut the burner down until it cooled then restart. Just another tidbit of info.

Steve