Heat Pump Furnace switch to override 4 degree

[jherber]

Howdy, my 2005 Itasca Suncruiser 35U TrueAir Thermostat switches the heat source to the propane furnace automatically if the temperature is set more than 4 degrees above the room temperature.

I remember reading about someone who added an on-off switch next to the panel to bypass this feature so one could set the temperature more than 4 degrees above the room temp and not allow the furnace to come on. This would sure help on cool mornings.

Where can I find that information? Thanks, Joe

[jbreault]

Reference this post:

http://www.irv2.com/forums/f101/tru-...tml#post395307

Looks like you could place a switch on the white wire to disable the furnace. Keep in mind that if you do disable the furnace, and the temps drop very low, you will be very cold in the MH as the heat pumps will stop generating heat but will continue to run.

[tderonne]

I'll see if I can find it later, but I recall a thread about Journey modifications where someone mentioned changing their thermostat to work on a time basis instead of 4 degrees. I think it was for AC, but the concept may apply.

[tderonne]

Post #19 here:

http://www.irv2.com/forums/showthread.php?p=2006687

[DancinCampers]

I added a switch on my previous 03 Adventurer. I spliced into the 3 wire pigtail from the t-stat in the one place panel. I had installed an Onan Auto Gen Start, so used the original generator start/stop switch hole.

You could also add a switch in line with the 12v circuit breaker for the furnace, on mine it was located behind the entry step panel. This would be awkward for frequent use though, unless the switch was located within easy reach.

[Duner]

Hey Joe, it's real easy to do. The gas furnace is is controlled by 3 -wire pigtail behind the Coleman Mach t-stat. All you have to do is cut the WHITE wire (pin3) and connect in a simple on/off switch so it opens the white wire. When I have "free" power at the campground I don't like to use up my propane.

So when you have the new switch open the gas furnace will not come on under any circumstances.

Bill

[Duner]

Originally Posted by Duner

Hey Joe, it's real easy to do. The gas furnace is is controlled by 3 -wire pigtail behind the Coleman Mach t-stat. All you have to do is cut the WHITE wire (pin3) and connect in a simple on/off switch so it opens the white wire. When I have "free" power at the campground I don't like to use up my propane.

So when you have the new switch open the gas furnace will not come on under any circumstances.

Bill

Let me add a little more on how to do this.....
The WHITE control wire is a low voltage 12v, low current signal to the furnace. Any small toggle switch will work, such as this one from Radio Shack: HERE

[Ray,IN]

My coach must be weird. I can walk in when the temperature is 50 deg., set the stat to 75, and the heat pump will run until the stat shuts it off.

[jherber]

It may be the design was changed somewhere along the way. I haves 2005 Itasca Suncruiser and the propane furnace comes on whenever the thermostat shows over a 4 degree difference. Have a great day! Joe

[D Lindy]

On our unit 2012 Journey the furnace does not kick on unless I set the Coleman "T" stat to the furnace setting, when the "T" stat is set to electric setting only the heat pumps come on even with a 15 degree difference.

[ghutch]

Just finished wiring in a simple on/off switch on the solid white wire on my single air/heat pump, single furnace system. The switch works and allows my heat pump to run for wider temp spreads. This will surely save LP in cool Spring and Fall weather. When turning on the electric heat, be sure the furnace switch is in the off position or the gas furnace may start up and it will take a few minutes to turn off after the switch is turned off. I'm glad I saw this thread.

[depchief]

Very interesting thread. My system works with the 4 degree differential, but both the heat pump and front gas furnace will run and the heat pump will eventually shut down and let the furnace run.
We were in 20 degree weather this winter and the systems worked fine. I would like to see a closer differential in the thermostat that seems to be 2/3 degrees. All of a sudden you feel cold and wonder when the system will start.

[Duner]

Originally Posted by depchief

....... I would like to see a closer differential in the thermostat that seems to be 2/3 degrees. All of a sudden you feel cold and wonder when the system will start.

One way to keep the temp more even is to set the FAN to ON for continuous air circulation. I think that helps some.