Furnace wont stay lit

86Stang

I've got a Goodman GMP075-3 model (I know, I've already read all the groans about the model so spare me the empathy lol). When we first turn it on, all is well, but the three flames will suddenly go out after about 5 minutes of running. All the blowers continue to blow but no flame. If it sits, shut off at the breaker for awhile, it will produce heat again but only for the five minutes or so and the same thing happens.

A few months ago the same thing would sorta happen but the flames would come on intermitently for awhile but then it just started working as it should. Now I get the problem described above.

I'm not an HVAC guy by any stretch but I'm mechanically inclined enough to try some quick fixes or even narrowing down my options so the guys in the know won't take me for a ride if I need to call on them.

Any ideas?

JohnH1

Check the led on the board in the blower area to see the code. It sounds like a hi limit is opening. Check the air filter and make sure it is clean.

86Stang

The air filter is sparkling clean.

The board is giving me one continuous blink. In other words ... blink ... blink ... blink. I take it that's not normal?

JohnH1

The both blowers running. I assume draft induser and main is usually a sign of a open limit. Main limit or burner roll out. Is the steady flash on the light durring the time both fans are operating and the furnace is down?

86Stang

By 'furnace down' I assume you mean when no flame is showing. If that's correct, yes, the light is blinking while the fans are blowing but no flame.

JohnH1

Strange. Not having a failure code. I would still think it may be a limit but would also suspect the board as also having a problem.

86Stang

So the steady blink of the LED light is normal? Usually a solid light means normal and if it's blinking, the number of blinks tells you what's wrong.

JohnH1

If I rember correctly a steady blink is a normal call for heat. For example 3 blinks with a pause the 3 blinks and so on shows there is a fault. Normally on the back of the blower door is the list of what the lights mean.

86Stang

How I could miss that?! The panel says:

1 Blink =

Problem:
Ignition Failure

Check:
Gas Flow
Gas Pressure
Gas Valve
Flame Sensor

JohnH1

Clean the flame senser it is the most common problem. Look for a single wire under the burners this will lead to the senser. it is normally on the left side.

86Stang

A or B?

and what do I clean it with?

Attached Images

 

SKIP4661

Clean A, do not touch B. Use steel wool or a scotch brite pad or sand cloth in a pinch.

86Stang

Will do. Thanks for the help both of you!