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ALANSD · 12-08-2006, 04:14 PM

In my 78 Sovereign there were two thermostats in the bedroom side by side. I assumed one was older than the other and was just left in place by a po.
I replaced the larger one with a digital and its working great, but then in the manual for the trailer I saw a photo of the same original two thermostats, the smaller on being an armstrong...its now disconnected...but what the heck was it for?
Seems like everything is working ok, heat included, so I am confused.

Alden Miller · 12-08-2006, 04:32 PM

My 1981 Excella has the same configuration. On top of that I found the guts of an old thermostat underneath one of the twin bed mattresses.

One works for Heat and the other appears to do nothing. This could be because the po replaced the AC unit and the controls are on the unit but I am curious.

-Alden

ticki2 · 12-08-2006, 04:56 PM

I have 2 in my '76 Caravanner also , not side by side . One is for the furnace , the other is for the AC , it has - cool-heat-off , the heat is for the heat strip in the AC . Hope this helps

overlander63 · 12-08-2006, 05:37 PM

The two seperate thermostats are, for one thing, because air conditioning used to be an option not everyone bought when the trailer was ordered. A thermostat for only the heat could be used on all units, and the air conditioner thermostat could be added.
Also, the furnace runs on DC, with DC voltage going to the thermostat, and the air conditioner runs on AC, and has AC voltage running to the thermostat, with IIRC, 18 VAC. AC and DC don't play well together.

ALANSD · 12-08-2006, 07:41 PM

ahh that explains it. I disconnected the Armstrong and did not seem to effect anything. I bought a home type digital thermostat for the furnace it works great so far. I first bought a mercury tube version analog, it was erratic in the trailer.