Wire a/c to thermostat

[gowyn]

Did a quick search to no avail.

In my '05 Bambi 19 I've replaced the thermostat with a household digital one for the furnace, works great.

Is it possible to also wire in the overhead a/c unit to the thermostat?

[FrankR]

Any thermostat can be used for controlling both heat and airconditioning....
if the thermostat was designed for both. Most modern furnacesand ac units work on milivolts but some use higher current. Read all the info about your control. Most modern t-stats will control both with no difficulty. My digital t-stat uses a 9 volt battery for a power source. Frank

[lewster]

Originally Posted by gowyn

Did a quick search to no avail.

In my '05 Bambi 19 I've replaced the thermostat with a household digital one for the furnace, works great.

Is it possible to also wire in the overhead a/c unit to the thermostat?

Gowyn,

Your Duo-Thermn A/C from Dometic comes with a local, manual control board and thermostat. This type of unit IS NOT COMPATIBLE with a remote type of thermostat. They do make a unit that IS, but you will have to change the entire unit to achieve this, as the manual controlled ones do not contain the required PC board and logic.

Also, Dometic units are only compatible with the Dometic brand thermostat that requires a 4 wire RC-6 phone type cable to run from the t/stat to the A/C unit. And besides, any tinkering with the unit WILL void YOUR 3 YEAR DOMETIC WARRANTY.

[Safari Tim]

Lew,

On the Dometics that are setup for a remote thermostat, when the trailer reaches the set temp, does the blower turn all the way off?

[nickcrowhurst]

For details on how I did this for a Coleman unit, click here:
http://www.airforums.com/forum...ace-14953.html?
It's been running successfully for two years now, and the digital wall thermostat is so much better than the original system.
Nick.

[Roadtoaster]

Originally Posted by nickcrowhurst

For details on how I did this for a Coleman unit, click here:
http://www.airforums.com/forum...ace-14953.html?
It's been running successfully for two years now, and the digital wall thermostat is so much better than the original system.
Nick.

Nick, forgive this possibly ignorant question but since I don't have the wiring diargram that you refer to I need to ask. You mention cuting the 120 volt line to the compressor and placing the relay in that line. Does that line also control the blower fan? Or said another way, is your system controlling the fan and compressor or just the compressor?

Thanks

Greg

[lewster]

Originally Posted by Safari Tim

Lew,

On the Dometics that are setup for a remote thermostat, when the trailer reaches the set temp, does the blower turn all the way off?

Hi Tim,

The remote t/stat is electronic and has continual (high, med, low) fan settings and auto. If left on auto, the blower will stop as well as the compressor when the setting is reached. It remains on in the other 3 settings.

[nickcrowhurst]

Greg, The fan is controlled by manually switching the AC "on" at the unit, as previously. The decision on which appliance (furnace or AC) is controlled by the thermostat is made by manually switching the wall thermostat to "cool" rather than "off" or "funace for heat" (a 3 position slider switch). When the slider is on "cool", the thermostat switches the compressor in and out as required to keep the trailer cool, while the fan runs continuously. It would be possible to switch both fan and compressor with the one slider, but I wanted the fan to keep circulating the air when the compressor was off.Good question. Nick.

[Safari Tim]

Great. That's what I was wondering. So when the coach reaches temperature all is quiet

Originally Posted by lewster

Hi Tim,

The remote t/stat is electronic and has continual (high, med, low) fan settings and auto. If left on auto, the blower will stop as well as the compressor when the setting is reached. It remains on in the other 3 settings.

[Safari Tim]

Nice job Nick.

I did that in a house once that had a window a/c unit. I just cut off the power to the whole thing with a relay when it reached temp.

Worked great when I sold the house.

Originally Posted by nickcrowhurst

For details on how I did this for a Coleman unit, click here:
http://www.airforums.com/forum...ace-14953.html?
It's been running successfully for two years now, and the digital wall thermostat is so much better than the original system.
Nick.

[Roadtoaster]

Originally Posted by nickcrowhurst

Greg, The fan is controlled by manually switching the AC "on" at the unit, as previously. The decision on which appliance (furnace or AC) is controlled by the thermostat is made by manually switching the wall thermostat to "cool" rather than "off" or "funace for heat" (a 3 position slider switch). When the slider is on "cool", the thermostat switches the compressor in and out as required to keep the trailer cool, while the fan runs continuously. It would be possible to switch both fan and compressor with the one slider, but I wanted the fan to keep circulating the air when the compressor was off.Good question. Nick.

Thanks Nick. Since I want to quiet the fan as well I will probably splice the relay into the main power supply line. I have a little humidity buildup problem. Have determined that the fan is creating a vacuum inside the unit and not allowing the condensate to drain like it should. Your thermostat idea gives me better temperature control and will likely cure my humidity problem as well by cycling the fan on and off.

Great tip and a lot less expensive than buying a new lower unit for my Penguin. By the way, did you happen to find a 120 volt relay?

Greg

[nickcrowhurst]

Originally Posted by ptrvr

did you happen to find a 120 volt relay?Greg

Greg, no, I haven't come across one. However, switching a DC current is more likely to create arcing than the same AC current, if I recall my high school physics correctly, so I'm content with the relay I have fitted. On the other hand, fitting an AC rated relay to switch the same current in DC would give me cause for concern.
Nick.