Thermostat

[mfMcFroggierPod]

Can you use a residential 24v/w Battery backup thermostat in a 12v system?
To replace analog thermostat in camper.

[SeaDog]

I think you may run into problems trying to operate a 24V stat on 12V why not just replace the analog with a digital stat designed for RVs. I just ordered the digital replacement for my analog (should arrive today) couldn't stand the large temp swings.

[donniedu]

If this is for an older RV with a basic thermostat, then YES you can. Quite simple really. There are lots of threads on this subject on the various RV forums. Basically what you want is a battery powered thermostat like the Hunter Douglas that I have. But there are a couple of others that work just as well. Download the wiring instructions and make the swap. Took me a couple of hours once I paid attention to what I was doing. I replace the batteries once a year whether zi needmto or not. Two AA batteries are pretty cheap.
If you have a newer RV with the crappy digital then your pretty much stuck.

[rockfordroo]

Quick answer: You can't use a 24volt T-stat in a 12 volt system.

Just get a battery operated one.

If you've got a Coleman-Mach, here's a wiring diagram for a Honeywell RTH111.

[Iwannacamp]

I saw this last night and wondered.... I have been doing a/c work part time for 30+ years and would assume the battery powered units would work fine. The switches don't care what voltage, the contacts don't care what voltage. If the processor part of it will function without line voltage(24V) then the rest of it won't matter. Most if the conventional a/c systems run on 24V AC not 12V DC... it wont matter for the switches, but might for the rest.
One more thing... the old residential stuff ran on 4 wires(no common/neutral) and when transistors came around they had to add another wire r/rc + rh...meaning 5 or more wires. Some use a jumper etc... It is not rocket science, but it can get complicated if you haven't practiced much on it.

I agree with SeaDog...just put a digital matching stat on there and the wiring will match.

[rockfordroo]

Originally Posted by Iwannacamp

I saw this last night and wondered.... I have been doing a/c work part time for 30+ years and would assume the battery powered units would work fine. The switches don't care what voltage, the contacts don't care what voltage. If the processor part of it will function without line voltage(24V) then the rest of it won't matter. Most if the conventional a/c systems run on 24V AC not 12V DC... it wont matter for the switches, but might for the rest.
One more thing... the old residential stuff ran on 4 wires(no common/neutral) and when transistors came around they had to add another wire r/rc + rh...meaning 5 or more wires. Some use a jumper etc... It is not rocket science, but it can get complicated if you haven't practiced much on it.

I agree with SeaDog...just put a digital matching stat on there and the wiring will match.

Not really sure, but I think the battery in the battery-backup T-stats usually just keeps the memory going. If there's no 24V available (i.e., power outage), the furnace probably isn't going to work, so the battery just needs to keep the memory intact until the power comes back.

So I don't think you want a 24v with battery-backup one, you want a battery operated one.

[Iwannacamp]

I e-mailed Robertshaw to see what they said....



Hello, Unfortunately we do not.





Jaime Torres
Technical Support Rep 2

jaime.torres@robertshaw.com
1222 Hamilton Parkway w Itasca, Illinois 60143 US
Office: +1 630 2607344 O Mobile: +1 630 2344110


-----Original Message-----
From: Chetty Cherry [mailto:cc@apsupply.com]
Sent: Friday, September 08, 2017 10:04 AM
To: Technical Services <technicalservices@robertshaw.com>
Subject: RV stat

Hello,


I was wondering...does Robertshaw make a stat that would be usable in a 12V D.C. RV application?



Thank you,


Chetty Cherry