Heater Thermostat

[Burnking]

I installed a digital thermostat. Honeywell 2 schedule. Ac works fine but no heat. Wires in Mini Lite 2304ks, blue,gray, green, yellow, white, red. Thermo contact strip calls for blue, orange, green, yellow, white, red. I put gray to orange. Red is jumpered. Thermo has switch to select gas/oil or electric/heat pump.

Any thought? Thanks

[Bama Rambler]

Did you take a picture of the wiring of the original T-stat before you unhooked the wires?

Do you have the models of the old and new thermostats that you could give us?

The switch should be set to gas/oil.

Here's how it should be wired, but there's no guarantee.

Red = +12v
Yellow = Comp
White = Furnace
Blue = Hi Fan
Gray = Fan
Green = -12v

[Burnking]

No photo. Seemed straight forward all wires the same except gray. Old thermo was Coleman Mach black. 2016 trailer. New thermo Honeywell RTH2300B. Is there a way to jump the wires to test heater? Worked fine with old thermo. AC works fine with new thermo.

[Bama Rambler]

I gave you Dometic wire colors. Here are the colors for the Coleman.

Red = +12v (Hook to ""R"/RC" terminal)
Yellow = Comp (Hook to "Y" terminal)
White = Furnace (Hook to "W" terminal)
Blue = -12v (Not Used)
Gray = Low Fan (Not Used)
Green = Hi Fan (Hook to "G" terminal)

You can hook the Gray to the "G" terminal if you want low fan speed instead of high (Not Recommended).

[Bama Rambler]

Did you get this worked out? I'd like to know if it is working for you?

[Burnking]

Turns out it is the wrong thermostat. Not 12 volt. Talked to Honeywell, tech asking me to check for 24 volts. Ask where that would come from!! Heat works fine if you jump white wire to 12 v supply. Will get a correct thermostat when I return home. Thanks for you assistance and concern.

[Bama Rambler]

None of these home replacement thermostats people are using to replace RV thermostats are 12 volt. They power the stat with batteries so you don't need 24 volts to the thermostat.

The people at Honeywell will tell you that it won't work, but there have been several people that have installed them in the RV's (me being one) and they work flawlessly.

Did you try it like I posted above for the Coleman hookup?

[Burnking]

Well then what am I doing wrong. I hooked it as you suggested. Did not run. I thought it worked at home because I was on shore power. Green to green, yellow to yellow, white to white and red to red. Blue and gray bot used.

[Bama Rambler]

Do you have the switch set for gas heat? Even if you do, flip it back and forth a few times and leave it set to gas/oil.

It's possible that you have a bad t-stat. There was one other report of problems and it was a bad t-stat.

[Bama Rambler]

Just covering all bases here.

When trying to run the furnace are you flipping the switch on the front of the t-stat to heat and raising the setpoint above ambient temperature?

I know it seems obvious, but I've done more boneheaded stuff when trying to figure out why something isn't working.

[Burnking]

I am home now running on shore power. Wired as you advised. AC runs but fan is on continuously. Heater does not come on when stat calls for it (switch to heat, temp set higher). You said you used one. What brand, model? Does fan cycle on/off when set to "auto" for AC?

[Bama Rambler]

I put the same model (RTH2300) in our last RV and the fan shut off when the A/C shut off when it was in Auto. The furnace also worked correctly when you put the t-stat in heat.

It sounds like you may have a bad thermostat.

[Burnking]

I will pick up another and give it a try. I will let you know the results. Thanks for all the help! I never thought it was rock science.

[Burnking]

Well I purchased a Honeywell HTH6350D today. Installed in 10 minutes and works like a champ. Heat & cool. Will return the defective HTH2300B stat.

[Bama Rambler]

Whoohoo! So glad you got it working. Sorry that you had all the trouble with the other unit.