Minor Emergency! My heater isn't working!

[GTHill]

So I'm leaving on a trip to Atlanta today and everything fired up on the coach (2003 40') except the heating system. The thermostat is on and seems to be functioning, but nothing will turn on. Fans, furnace, nothing. I looked at the circuit breaker panel underneath the bathroom sink, but it doesn't have a label for anything related except for AC. Any help would be greatly appreciated!

GT

[Old Scout]

see note above on Dometic thermostat...make sure you are using zone one and check the 12v fuse....

[GTHill]

Zone 1 is set to heat pump and fan to auto. If I turn the fan on manually, it doesn't come on. The thermostat is on and functioning.

Where is the 12v fuse you are speaking of? If it was bad, would the thermostat display still come on?

Thanks for the help!

GT

[Jim A]

The circuit breakers are for the 120 volt items. There should be a fuse panel in the same area that has automotive type fuses in it. Mine is in the bathroom, behind the panel near the floor. One of those should be for the furnace, which is 12 volt. (I am assuming you don't have the Hydrohot?) My fuse panel was labeled, so it was easy to see which fuse was which.

In the first year, my furnace failed. It was traced back to a faulty board in the furnace. The replacement board failed during testing at the dealer. They had to use an upgraded board. Something about too high of a current flow, from what I remember. It was a furnace problem, not a WRV problem. It was 4 years ago. In that case everything else still functioned. I could use the heat pumps and the air conditioners. Just no furnace.

[takepride]

GT:

The 12 volt fuse panel is right under the 120 volt AC panel, under the bathroom sink.

Mine were not labeled, so I made a hand-written chart of what didn't work when I pulled the fuse. Lights, fans, furnace, hose reels, water pump, thermostat, etc. BTW the thermostat and the furnace are on different 12v circuits.

Also make sure you don't have one zone set to heat pump and the other zone set to furnace. It just confuses the thermostat.

The thermostat is 12 volts, the heat pump is 120 volts and the furnace is 12 volts.

[Dave Fernandez]

Hello GT:

I would also look at the circuit board the Dometic boards are known to fail. You can get a replacement from Dinosaur Electronics or from Dometic.

[work2play]

If you PM me I can send you a troubleshooting guide that I just got for the Duo-Therm Comfort Control center. It is about 5MB. I just had similar problems with mine but my symptoms were different. My thermostat did not have any power. ended up being a 3amp fuse on the board in the front AC.

[GTHill]

I really appreciate the help. After leaving the generator on for 15 minutes or so, I went back out to the coach and the heat pump was running. I guess there was no problem, but it did take quite some time for it to come on. While on the trip, it comes on quickly. Maybe the batteries were low? Thanks!

GT

[Jim A]

I have noticed on my coach that it always takes a few minutes for the air conditioner or heat pump to start after turning on the thermostat. However, if I turn on the thermostat before I plug in, the air conditioner starts quicker. It appears the thermostat has the time delay built into it. Turning it on (12 volt system) before plugging in starts the timer on the delay. If you had low batteries, that probably didn't start the timer.

[takepride]

Good catch Jim.

The thermostat does have a built in delay. I've noticed the delay is different under various circumstances. I know a restart takes the longest. I'll have to try your method. I'm not sure how the delay is made, but the timing is inconsistent. Maybe the battery condition is an influence.