Install Honeywell RTH111

Old-Biscuit wrote:
Coleman Mach to Honeywell

Coleman

Red = +12vdc
Blue = -12vdc
Green = Fan High
Gray = Fan Low
White = Furnace
Yellow= Compressor

Honeywell

Red = +12vdc -----'RC/RH'
Blue = -12vdc NOT USED/Tape off
*Green = Fan High ----'G'
*Gray = Fan Low ------'G'
White = Furnace .....'W'
Yellow= Compressor ,,,,'Y'


*Green and Gray are used for the A/C Unit fan speed
If you do not install/modify your thermostat with a mini switch to have/use both Hi-Lo fan speeds just connect GREEN (Fan High) to 'G' terminal

If you wanted the fan to run on low, then you would connect the GRAY to "G". Right ?

Thanks,
Dusty

On Coleman Mach T-stat, power to operate the electronics comes from the 12V DC (+) (RED) and the 12V DC (-) (BLUE) is required to do this (complete circuit).
Hunter T-stat uses 'batteries' for it's electronics hence the 12V DC (-) is not needed.

Old-Biscuit wrote:
Coleman Mach to Honeywell

Coleman

Red = +12vdc
Blue = -12vdc
Green = Fan High
Gray = Fan Low
White = Furnace
Yellow= Compressor

Honeywell

Red = +12vdc -----'RC/RH'
Blue = -12vdc NOT USED/Tape off
*Green = Fan High ----'G'
*Gray = Fan Low ------'G'
White = Furnace .....'W'
Yellow= Compressor ,,,,'Y'


*Green and Gray are used for the A/C Unit fan speed
If you do not install/modify your thermostat with a mini switch to have/use both Hi-Lo fan speeds just connect GREEN (Fan High) to 'G' terminal

Thank you so much for this post. I just installed the new thermostat and all systems are working great. I am just curious why the blue wires are used in the Colman but not the Honeywell. Once again thank you!!!!!

SRockwood wrote:
Automotive DC power only has a couple of standards: red is hot, black is ground.

RVs do not "follow" "automotive" DC power color codes for "house" power.

Instead they follow HOME AC wiring in which WHITE now becomes battery ground (negative terminal) and BLACK and any other color can be battery Positive..

It is typically done this way since the manufacturers will have only ONE electrical team do all the wiring for both 120V and 12V..

Clear as mud?

Automotive DC power only has a couple of standards: red is hot, black is ground.

Coleman Mach to Honeywell

Coleman

Red = +12vdc
Blue = -12vdc
Green = Fan High
Gray = Fan Low
White = Furnace
Yellow= Compressor

Honeywell

Red = +12vdc -----'RC/RH'
Blue = -12vdc NOT USED/Tape off
*Green = Fan High ----'G'
*Gray = Fan Low ------'G'
White = Furnace .....'W'
Yellow= Compressor ,,,,'Y'


*Green and Gray are used for the A/C Unit fan speed
If you do not install/modify your thermostat with a mini switch to have/use both Hi-Lo fan speeds just connect GREEN (Fan High) to 'G' terminal

golden Havac, if I understand your information correctly, I should connect the +12 volt DC, in my case a green wire to the red terminal. Do you agree?
This is not a programmable tstat.

The thermostat will use DC power to run the items.

Standard operation of a home thermostat is for the wires to be used as listed.

R terminal, a red wire, and probably connected to the ungrounded 24 VAC (in a home, and in the case of MY RV ( a fleetwood Bounder) it is +12 volt DC))

G terminal green wire that normally when energized will turn on the indoor fan.

W terminal, normally the white wire and will normally turn on the heater

Y terminal, normally a yellow wire that will normally turn on the cooling system

C terminal is normally used in programmable thermostats and would be the grounded 24 VAC system in a home, but not normally needed in the standard RV application. They might have used any color wire for the C terminal. I normally would use black or brown wire for this connection when installing a system in someone's home or business, but there is not a 'standard' color, so normally I would be looking at the thermostat, or the heating unit to determine what color was used for the 24 volt return wire.

You might also find another terminal on a home system. It might be O terminal or B terminal, and might use the Orange or Blue wire, it is most common on a heat pump, and will activate the reversing valve. This is sometimes energized in heating, but more commonly is energized in cooling. This is because should the reversing valve break, default to heating is desired. Yet I was working on a newly installed heat pump last week, and the resident complained that it was blowing out cold air, I found a poorly connected orange wire at the O terminal, and quickly solved the problem! By making this connection, the reversing valve was energized, and it went from cooling the room to heating it.

What I would put into my RV if I installed a programmable thermostat would be the Honneywell 6000 series, where it is powered by a pair of AA batteries, and has the ability to shut off, auto change over from heat to cool, and does not require it be run on AC power or DC power. Do not use the Common wire with a DC power system, as it is designed for 24 VAC only between R and C terminals, or can be run from the DC battery included with the thermostat.

Good luck with your project!

Fred.

There is no set wiring color codes in the RV industry. However the idiots at the factory wired it is what it is.