Thermostat?

[Goodjuju77]

I have bought a 1991 duchman classic 300 and I do not have a thermostat anywhere to be found (was in very bad condition and had many home modifications) and was wondering the cheapest and quickest fix......it's soooo hot

[sundancer 87]

Originally Posted by Goodjuju77

I have bought a 1991 duchman classic 300 and I do not have a thermostat anywhere to be found (was in very bad condition and had many home modifications) and was wondering the cheapest and quickest fix......it's soooo hot

Do you have a roof mounted A/C?

[Jayro88]

I have a 1994 Classic 300. Probably the easiest way would be to buy some new thermostat wire and just run new.

If you want to kick you AC on, assuming it has power, you can jump the wires at the unit to turn it on. That way it could cool off in the trailer for you to work.

You can install a battery powered residential thermostat.

[franktafl]

Would your thermostat control the heater too? Not sure a residential thermostat will work.

[persistent]

I have a 2018 Dutchman Kodiak Cub. It has a wall thermostat for the furnace. It does not have a wall thermostat for the roof mounted air conditioner.
Both furnace and air conditioner may have temperature control on the unit themselves.

[acdii]

Home thermostats are not to be used for RV AC, it can damage the control box. If there is no thermostat, then the AC may have controls on the unit itself, or did prior to you getting it.



You have two options, first, get an RV thermostat, which requires running wires up the wall and across the ceiling, or replace the AC control box and grill with onboard control box and matching grill.

[Jayro88]

Originally Posted by acdii

Home thermostats are not to be used for RV AC, it can damage the control box.

Can you please explain this? A residential thermostat that does not have the option to run off a battery can’t be used because it draws its power from the 24v (iirc from my hvac days) that comes in on the red (usually) wire from the AC unit control board. Since the trailer unit runs off 12v it doesn’t work.

Past that, the thermostat is basically a relay system that completes the circuit from the red wire (12v in our case) to the yellow and blue (AC call and fan). This closes the relay on the unit and feeds the compressor and fan motor shore power (or generator).

You do have to do a little investigation to figure out what thermostat wire does what since it doesn’t follow the exact same scheme as 99% or the residential units.

What am I missing?

[acdii]

Of the two I have been researching, Coleman and Dometic, they clearly state to not use with a residential thermostat as it can damage the control unit.



The main difference is the fan setting, RV fans are low and high, no on/off like the home one has.



If using a battery powered one, then a switch will be needed to change from high to low. Also a home Tstat does not have a ground bus like the RV one does. This leaves an open ground between the control box and vehicle 12V system.



I will see if I can find the statement regarding the use of a non RV Tstat, but I did that on my home PC and I'm at work.

[Jayro88]

Originally Posted by acdii

Of the two I have been researching, Coleman and Dometic, they clearly state to not use with a residential thermostat as it can damage the control unit.



The main difference is the fan setting, RV fans are low and high, no on/off like the home one has.



If using a battery powered one, then a switch will be needed to change from high to low. Also a home Tstat does not have a ground bus like the RV one does. This leaves an open ground between the control box and vehicle 12V system.



I will see if I can find the statement regarding the use of a non RV Tstat, but I did that on my home PC and I'm at work.

Thanks for the info.

I would be interested to read what you find.

[Jayro88]

Originally Posted by Jayro88

Thanks for the info.

I would be interested to read what you find.

Also, you are correct about the low and high speed fan. With just the home setup you are stuck using either just the low or just the high. You can add a small switch so you can manually toggle between the 2.

[acdii]

I went through my history last night, and found what I was looking for. Aside from the lame warranty exclusions which don't specifically state thermostat, I found where a question was asked on Amazon for a Dometic Brisk II, and one person replied that he used one on his and caused an issue that the warranty denied.



A lot of the control boxes I was looking at stated to use a specific thermostat as well, so YMMV on this particular item. Besides, RV thermostats aren't any more costly than a home one, they are just not readily accessible without online shopping.