Forced air heating problem

[jimwall2000]

Hopefully someone here can give me some ideas on what might be wrong with my Day and Night heater (about 10 years old). Every few days it fails to come completely on and it flashes a Ignition Proving Failure warning message. But the other 98% of the time it works perfectly.

The details: - It seems to do this in the early morning when it is changing from the lower night setting to the higher day time setting. - Removing power to the heater, waiting 5 minutes and turning it back on seems to always fix the problem (based on three to 5 times) - The thermostat was replaced and did not fix the problem - The sequence is: low speed fan comes on, electric igniter glows, gas jets are ignited, a few seconds later the gas is shut off, error message flashes, fan continues to run for a while, then the sequence repeats.

Thanks for any ideas that I can try for myself.

-Jim

[tony]

sound like you may have ventilation /draft problem Tony

[Dr. Hardcrab]

Replace the thermostat 2 more times.

Remember: 3rd time's a charm...

[Bubba]

"Hey, Hey, Hey..........That's my line" Bubba :-)

[Dr. Hardcrab]

Ooooops!

Damn! I'll add it to your monthly royalty check.....;-]

[Tony Hwang]

Hi, Did you have a reasonable cause to replace the thermostat? First, up front what is your furnace make and model? Think logic. After ignition, it is time for the flame sensor to tell the logic board the flame is on. So what do you think. If all the logic flow is not correct step by step, furnace shuts off for safety. When turn the power off/on, you are resetting the logic. Or it'll reset itself after fixed number of hours. BTW, no diagnostic code when it is acting up?

[Zyp]

That's it. Logic from someone who doesn't understand the english language.

[CJT]

That includes much of the U.S. population these days.

[Zyp]

Seems so. The kids today can't speak well. In fact, some of them speak so fast, you can't understand a single word. Or is it that they don't use periods? Maybe it's that text-speech thing?