Furnace this morning--nothing?

Hello,
we have a BH 3670---2010---this morning I moved the thermostat up and got nothing from the furnace. I checked wires in the thermostat, putting one on ground and the other going to each colored wire and have voltage to each. The fan will not come on. I checked the fuses and all seem to be ok--then had wife look at fuses and put the thermostat on and all fuses were ok. I then turned on the air with the thermostat and it worked fine (meaning the thermostat is ok???). Where should I look next---LP is fine, both tanks are full.
thanks
al

If the furnace blower doesn't come on, I would re-check the fuses using an ohm meter. If the fuses check out, you may have 1) a loose wire at the furnace or a 2) bad control board.

The thermostat signals a relay above the air conditioner return in the living room. So that's another possible point of failure - but less likely. (On edit, if your 2010 coach has a Dometic LCD digital thermostat this is true, but you may have an analog thermostat in which case I believe the 12V to the furnace blower goes through the thermostat - if you're measuring 12V DC at the thermostat wire, the problem is probably on the furnace itself.)

And if by chance you've set up a heat source in the basement plumbing area, the rising heat could be confusing the thermostat by warming up the backside of the wall the thermostat is mounted on.

Have had similar issues. Replace the fuse. May look ok but may not be. If that's not the remedy and you checked connections on the fuse block and on the furnace it's likely the board. Been there, done that!!!


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Our furnace (2009 BH3670) quit working like that at the end of last season. Ended up being the circuit board on the furnace. Board was $116, dealer diagnostic and service, another $129.

As I recall, there are something like four components on the furnace proper that can go wrong. For me to try to repair it probably would have been trial and error and ending up costing more in both $$ and time.

If you're comfortable pulling the furnace out of the rig, have a place to work on it and doing the troubleshooting, there are videos on YouTube.

Thanks everyone----this is by far the best place for information and ideas---yes, it was the board---I did get it replaced and all is fine now--learned a few things for future--appreciate all your help
currently volunteering at Crystal River National wildlife
al

aatauses said:

Thanks everyone----this is by far the best place for information and ideas---yes, it was the board---I did get it replaced and all is fine now--learned a few things for future--appreciate all your help currently volunteering at Crystal River National wildlife

Click to expand...

You sir...are a rock star. Posted the problem 7 hours ago...read a few inputs here...then you were able to source a new circuit board...pull the heater..exchange circuit board...put everything back together....all in 6-7 hours.

Hats off to you!!!!