Thermostat or furnace ??????

[High Ball]

Happy New Year to all !!!!!

We left home in -17f a couple weeks ago and since the dash heat wasn't enough I started the furnace and she ran all the way till evening. She ran for about 10 hrs. the next day all was fine, no furnace running. 2 days after while driving, the smoke alarm went off, what a nerv wracking for a few seconds while wife went to look. I stopped the MH in a secure area and didn't smell smoke but realize that fan on furnace was running. Thermostat was on position with all on off modes but fan kept running. I switched the under slid button to off and it didn't stop. I had to unplug the wires from heater. Now if I turn the under switch to on and put furnace on only blower goes on but no flame. If I turn selection to Off and under switch to off, fan won't stop without unplugging the wires from furnace.

Would it be a thermostat problem or furnace ??????

I have the 5 button Comfort Control thermostat and a Hydro Flame 8520IV furnace.

All other functions ( heat pump front and back, AC front and back,rear heat) seems to work OK

1- Can I do a Thermostat reset ???? Is it do-able ???? Will I loose all other functions ????

2- Would it be a burner problem on furnace ????? Why doesn't it shut down with remote???

3- The smoke detector going off, ( right above thermostat) would it be the thermostat shorted out only on one section (furnace) ???



Any input would be greatly appreciated

[WeatherTodd]

check the control board and the propane fitting.

[FatChance]

Is there propane in the tank?

[Triker56]

If you left a couple weeks ago and headed south.
You should no longer need to use a furnace. And be in a warm area that only the AC is needed.
Or you are driving too slow every day.

[Quincy]

Originally Posted by Triker56

If you left a couple weeks ago and headed south.
You should no longer need to use a furnace. And be in a warm area that only the AC is needed.
Or you are driving too slow every day.

You kidding we are in Ocala Fl. and it is in the forties

[Quincy]

The short answer is with all the pc boards and electronic controllers connected to the furnaces nowadays who knows what the problem could be.

Now after relieving your stress with the above comment... I believe it could be the stat or the furnace ie, fan relay (someone posted a while ago that some units use a sail switch on even newer rigs.) Stat could be shorted or the wiring could also be shorted, which is really unlikely.Just give the blower motor time to shut off as it does not go off when the stat is satisfied but after it has removed all the warm air from the ducts.

Good luck and keep us posted.

[OLYLEN]

How is the battery level, charge? With the alarm going off low voltage? As to the furnace take the thermostat off the wall unplug and telling. Do the same with all connections at furnace also. A reset might help also and should not affect operation.

LEN

[tmw188]

Turn off the 12v power to the house that should turn off that fan, then turn the 12v power back on again and that should at least cancel out that fan, sort of a reset. If the fan comes back on it could be the stat or a relay whatever controls that. Then try to do a start up again with the furnace to see what happens. If that doesn't work maybe a flame sensor? Look in your manual for trouble shooting.

[High Ball]

Thanks to all for the replies.
yes propane tank is at 3/4 and all others propane appliances are working
I have enough voltage 12.8-13
I did shut off main power, un plug thermostat, re tried and same thing. No flame and blower keeps on running.
I took outside panel off, took main board partially off and un plug all wires, re plug, play tried to see if some of resistors, relays and other things on board if they were slack and re install board. Can't seem to find sail switch by following wires.
tried furnace again twice and for now all seems good.
bring temp up, furnace and burner starts, bring temp down , burner off and blower off.
guess if I have further problems it will be time for new card.

thanks again for all info, Greatly appreciated.

[Pepper2]

Pulling the wires off the terminals and reinstalling them may have cured a poor contact on one of them.

We are in the RGV and woke up to 36 degree temps. Brrr...

[tmw188]

You have an Attwood furnace correct? Do you have the manual for it?


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[Quincy]

Sorry I misread your post the first time about no flame. I would pay close attention to the control board since it seems like two different failures at the same time, If you can get a picture or at least a good look at the back of the board you might see a small yellow spot where the board got hot enough to damage the circuit.

keep us posted please.

[High Ball]

Since we are going to get a few nights of under 40 decided to try furnace today and same symptoms. Played with wires and stuff on board but just blower goes on and won't stop until I unplug main one on furnace. Just order new Electronic board for furnace. will only get it next week then will see if this is really the problem

[WeatherTodd]

funny thing... my board went out. I always keep a couple of electric space heaters in the coach out of habit. Glad I did. Temps dipped into the 30s... and the coach thermometer showed it being 48 inside! Didnt help someone left the windows open while pulling down the night shades.