wiring replacement thermostat

mitechie · 10-10-2013, 03:12 PM

I'm fighting to replace that awful thermostat that came with our x23b. It's heat only, two wires. Red and white. Silly me, I thought this would be easy.

I purchased a Honeywell T87K heat-only thermostat which was great. Two wires, go. Except it had no switch to turn the heat on. So I figured it'd just work off the temp but setting it to 80+ and waiting and it would never kick on.

So then I read that I need fan control. So I bought a T87N which is much more complicated. It's got controls for air, fan, and heat. Except I've only got two wires. I wired it up, set the temp for 80+, turned the fan to on, the control to heat and nadda. Taking red to red and white to white I'm missing a wire for the fan control hookup on this unit it seems?

Anyone have any hints for me? I know there's other threads on this and I've poked around but it seems to be 'it matches wire for wire' with folks with a different setup.

mitechie · 10-10-2013, 03:25 PM

Here's a pic of the N unit.

glsimms · 10-10-2013, 03:25 PM

I'll be following along as I am also looking to change my mechanical thermo with a digital.......

Doug · 10-10-2013, 03:35 PM

I found this thread.
http://www.jaycoowners.com/showthrea...ostat-Problems

It seems most people are using a Coleman 12V RV Thermostat.

The thermostat you reference looks like a 24V unit? Could that be the issue?

Doug

mitechie · 10-10-2013, 04:08 PM

Bah you're right. Put the digital one I also have here on and boom it works. Missed that these Honeywell ones weren't going to work. Thanks for the reminder to read all of the manual.

glsimms · 10-10-2013, 04:29 PM

Which one did you use? A Hunter digital??

mitechie · 10-10-2013, 04:32 PM

Quote:

Originally Posted by glsimms

Which one did you use? A Hunter digital??

I used one of these:

http://www.amazon.com/gp/product/B00...?ie=UTF8&psc=1

I saw it recommended elsewhere and ordered it at the same time as the honeywell. I had really hoped to not use it since I didn't want to use something that required batteries and I LOVE the look of the old dial thermostats but the 24v thing wasn't going to work doh!

With this one I pulled the red jumper off, wired the two wired up, and voila it's magic and works.

glsimms · 10-10-2013, 04:36 PM

Thanks mitechie....

msturtz · 10-10-2013, 04:41 PM

I spoke with Coleman and you cannot use a residential thermostat. It will eventually destroy the electronics in the heater or AC. I have a heat pump plus propane for low temperatures. I wanted to install an automatic residential heat pump thermostat. They said to not do it. They said that 24VAC thermostats will not work.

mitechie · 10-10-2013, 04:52 PM

Pic of the unit up there now. Ready for this weekend.

Doug · 10-10-2013, 06:06 PM

A mod on my list :-)
I usually get by with an electric heater, but do supplement with the furnace occasionally.
I don't care for the thermostat in my 165 Sport.

Looks good. Enjoy,

Doug

msturtz · 10-10-2013, 06:52 PM

Quote:

Originally Posted by msturtz

I spoke with Coleman and you cannot use a residential thermostat. It will eventually destroy the electronics in the heater or AC. I have a heat pump plus propane for low temperatures. I wanted to install an automatic residential heat pump thermostat. They said to not do it. They said that 24VAC thermostats will not work.

The technical representative said that residential battery powered units will appear to work for a period of time however will burn out the control module eventually. The reason for this is even the battery powered units are designed to control a 24VAC circuit not a 12VDC circuit. It may work for even a several months depending on usage but eventually you will have a problem. They get a lot of warranty claims for AC units that have failed for this reason. I don't know about the heater in your specific unit but that is what Coleman told me for the ones in my Greyhawk. I wanted to check with the manufacturer prior to modifying my rig because I don't want warranty problems.

Bikester · 10-10-2013, 06:53 PM

I'm doing this for sure, thanks Mitechie

mitechie · 10-10-2013, 07:18 PM

Msturtz I checked and this unit specifies the voltages required and it's low. I could tell the difference once I looked at the Honeywell as its low voltage spec was 20.

chuckworkb · 10-11-2013, 05:45 AM

In my 19H I took out the original heat thermostat, and installed a coleman thermostat that runs both the heat and the AC. It took rewiring the AC unit and disconnecting the AC thermostat in the AC unit itself, and using a couple of relays, but it works GREAT! Now the fans turn off when the AC turns off, which I wanted, I have better control of the actual temperature in the camper. Plus the heat is also on the same thermostat, so that's an added benefit. I used it all spring and summer without a problem.

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