A/C & furnace control issues

Symptoms:
1) Furnace will not turn off once setpoint is reached. We have to go to the thermostat controller and turn the unit OFF. Furnace then does normal shutdown. Furnace comes back on once we turn the thermostat controller back on.
2) A/C will not turn on when setting thermostat to Cool / Fan Auto.

Specs:
Dometic 5 button Comfort Control Center Thermostat
Suburban SF-42 furnace
Dometic Penguin II low profile A/C

Steps taken so far:
Power cycled 12v system
Power cycled 120V system
Checked fuse for thermostat
Replaced the thermostat (I had a back-up unit)

Unique events recently:
We are in Texas, and had a really cold spell recently with snow. These symptoms began during this cold spell.
We also had short rolling blackouts for a few days.

Any ideas on things to look at and troubleshoot would be helpful. Thanks in advance!

 

Hi and welcome to the forum. Sorry to hear you are experiencing problems with your AC and furnace. I am by no means an electrician but I do know a few things about what you are going thru. Those rolling blackouts you mentioned could very well be the cause of this. Power outages along with even "brownouts" can do weird things to the electrical system in an RV. The fact that the furnace does still run, just not properly means that the fuse for it has not tripped however in that the AC will not turn on could mean that the fuse for it has tripped? Also did you by chance check the main circuit board that is usually located in a storage bay? Something there could have been shorted out? If everything was working okay prior to the outages and cold weather, etc. chances are it is a fuse or even a capacitor, etc that can be changed out once found. Again, if you are unable to find the "culprit" best to get a pro to come check it out IMHO. I'm sure someone else on the forum with a lot more electrical knowledge will jump in shortly and possibly be able to add more assistance than I am able to give. Let us know when the problem is resolved and what the cause was as this will be of future help to others that may experience the same thing. Safe travels ahead to you. Also be sure and post a review of the RV parks and campgrounds you stay at, on the flip side of this site......

Regards, BankShot..................(aka Terry)

 

I wish I could give you some concrete advice. My first suggestion would have been thermostat and obviously it was yours as well. The circuitry is simple but components in today's appliances can get complicated. If your problem was that the furnace would not run there are safety devices that could be the problem, high limit switches and such. Clearly, a message is not being delivered to say "turn me off" so that is where one must look. I suspect there is, built into your system, the means to not allow your AC to operate if the furnace is in use. A stab in the dark is that might be your AC problem. As BankShot suggested, me thinks this is the job for a pro.

Darrell

 

Thank you very much for the information, and welcome to the forum. By the way, I once had similar problems with air conditioning. Something happened to my electronics, and it was constantly working poorly. I tried all the methods from the Internet, but nothing helped. And I decided to contact the service for the repair and cleaning of air conditioners. I gave them my air conditioner, and they set the amount I had to pay. It turns out that the electronics worked incorrectly there since the radiator was dirty and thus did not allow the air conditioner to function correctly. It's good that it all cost me cheap because I had a friend working in this service.
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Thanks for the info, but i doubt too many of us will be driving our RVs to Singapore.

 

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Whattsa matta you Fitz, you no got pontoons for your RV.............

Sail Away, Terry.............(aka BankShot)