Thermostat swap to digital

[r1johnson]

Your home unit is actually 220 volts but it has transformers that step that down to low voltage for things such as this, in the thermostat there is a relay that opens and closes to complete a circuit that starts and stops the unit based on it's set temp. On older thermostats that are not digital they still had a low voltage lead coming from the unit and that circuit was completed by the thermostat when the temperature reached the setting. Residential typically use 24 volts ac as the low voltage, campers operate on 12 volt dc systems for things like this, not sure how the one you hooked up is working but glad it is, i replaced my mechanical thermostat with the colman digital and it works great, good luck with what ever you do.

[us71na]

Originally Posted by r1johnson

Your home unit is actually 220 volts but it has transformers that step that down to low voltage for things such as this, in the thermostat there is a relay that opens and closes to complete a circuit that starts and stops the unit based on it's set temp. On older thermostats that are not digital they still had a low voltage lead coming from the unit and that circuit was completed by the thermostat when the temperature reached the setting. Residential typically use 24 volts ac as the low voltage, campers operate on 12 volt dc systems for things like this, not sure how the one you hooked up is working but glad it is, i replaced my mechanical thermostat with the colman digital and it works great, good luck with what ever you do.

If your home thermostat uses batteries, it "may" or "may not" just act as a set of switches to control the various functions. However, if your home type thermostat has no batteries, it needs 24 volts AC to operate the thermostat itself and it will not work on a 12 volt DC system.

[Vaquero]

His runs great. On high fan speed of course.

[Farmall]

I was thinking of switching out my Coleman-Mach for a Dometic digital. Is the wiring the same - 6 wires and the color codes?

[RVJayhawk]

Would it never shut of or just in the heat mode?

[DNelson]

When I switched from the factory Coleman analog to digital I had a lot of problems with the thermostat resetting itself to the factory 72 degrees. When I called Coleman they said the only reason for that would be a loss of 12 volt power or a voltage drop to the thermostat. I then read a thread here stating that the 12 volt power was provided by the heater and when the furnace fan would start the voltage dropped. My solution was to run a separate 12 volt wire directly from the trailers power supply. I simply found an unused 12 volt fuse connection in the power supply, put in a 15 amp fuse and ran it to the thermostat.

So, sometimes even the Coleman factory digital thermostat needs a hack. And agree with the poster who said it is a cheaply built thermostat and looks like it was built in Japan in the 50s or 60s. When I put an AC unit in the bedroom I just purchased a LUX TX100EZ battery (2 AA) operated thermostat with backlighting for $20. It was simple to install even though Jayco had used odd colored thermostat wires.

[RVJayhawk]

Originally Posted by Johnyb6633

the wires match fine. I used a simple Honeywell TH3110D1008 Pro Non-Programmable Digital Thermostat. yeah i dont have A/c hooked up to it. But its a simple upgrade and works fine with the heater in my jayco.


see pics

Did you get the cooling hooked up? I have "upgraded" to the same thermostat in our 2017Melbourne. It works great on the AC , but not on the furnace. The furnace fan comes on, but the burner will not light. And the AC fan wants to run constantly. And I have to admit, based on comments from the Jayco salesman we dealt with, I thought we had a heat pump. I was trying to diagnose a problem with the AC reversing valve, but alas, it doesn't have one since it is not a heat pump.