change out thermostat, Digitial Thermostat Options

[Ron6532]

We want to be able to change to a digitial thermostat from the one that came on the trailer.

Does anyone know if this can be done?

I was told I could replace it with a Hunter but Iwould have to change the wiring.

Thanks

[Stanley P. Mille...]

A lot depends on which one you have now. What brand and model do you have now?

[Ron6532]

A lot depends on which one you have now. What brand and model do you have now?

We have a Duo-Therm and I can't find the model number. It has a 2 speed fan on the a/c.

[Viv and Bill]

We have a Duo-Therm and I can't find the model number. It has a 2 speed fan on the a/c.

Yes, it can be done, I just did this a couple of weeks ago. Went to Walmart, bought the Hunter 42999B thermostat for $19.95+tax. Installed in less than 30 minutes with wiring as follows:

WIRE_________DUO-THERM______HUNTER
Ground_______Green___________"RC" and "RH" - already jumpered on the Hunter
Fan__________Tan(or Brown)____"G", see below(High Fan)
High Fan______Blue____________"G", see above(Fan)
Cool__________Yellow__________"Y"
Furnace_______White__________"W"
Red 7.5vdc_____Not used, capped, taped, return to wall for future use.

Note that I tied the High fan and fan together. I wanted high fan whenever air-conditioner was on. If you wanted, you could add an external switch to do this by wiring the High fan through the external switch to "G". This would then give you both speeds, I didn't need or want this. The Hunter uses two 1.5AA batteries and according to the manual lasts about 1 year, with a warning (flashing numbers) when they get low. We've been extremely happy with this unit, and gives us accurate control over the temperatures. Have used both the heat and air-conditioner without any problems. The in-accurate slide switch on the Duo-Therm made setting temperatures extremely hit or miss. Hope this helps.

[Asawang]

Does anyone know what the correct corresponding wire colors would be for a Coleman Model 7333B891? I have emailed RV Support at Coleman but have not gotten a response.

[lakejumper]

Here are some directions and pictures that are from RVers Corner -
Hunter Digital Thermostat Install

This post has been edited by lakejumper: May 15 2009, 08:04 PM

[Alfa38User]

Does anyone know what the correct corresponding wire colors would be for a Coleman Model 7333B891? I have emailed RV Support at Coleman but have not gotten a response.

Here are the colours for Coleman 6535A336 (RV Comfort - Coleman Mach) They are likely very close to what you are looking at (2 stage Heat pump and dual compressor A/C: ) I hope the formatting holds!!!

Lifeline to Heat pump/Air Conditioner in 9 pin plug

W Heat Pump white/black Plug terminal 8
GH Cooling High Fan Black 7
B -12V DC Blue 4
F Freeze Switch Gray There are 2 of these, each to a different terminal in the plug 1 & 3
R +12V DC Red 2
Y1 Compressor #1 Yellow 5
Y2 Compressor #2 Orange 6
GL Cooling Low Fan Purple 9

Thermostat power: 3 pin plug
R 12V + Red
B 12v - Blue
W Furnace control White


I see that you are dealing with a smaller trailer A/C so I suspect not all leads are present such as those associated with the heat pump. Did you check their web site at RV Comfort ( Coleman) for information? They have quite a few documents available on line.
HTH

This post has been edited by Alfa38User: May 16 2009, 08:41 AM

[Russell]

Thanks for posting this, I had thought about a digital thermostat for a long time, but was thinking I had to have one made just for RVs.
Went to Walmart this morning, picked one up (almost grabbed the programmable one for $5 more, but decided it wasn't necessary.)
Just got through installing it, works great.

[Asawang]

Thanks for the information and sorry I didn't get back before. I heard from Coleman and they said I can't use that thermostat because it is a 24V thermostat and I have a 12V air conditioner. After reading the responses here I am wondering if they are correct or just want to sell me a thermostat. Is this correct? Does the thermostat actually operate off of the 24V or does it operate off of the battery power? I thought the batteries provided the power to control the thermostat and it would handle up to 24V. Otherwise why are the batteries there and why does it not work when they are dead? I just don't want to cut all the wires off of my old thermostat and then have to put them all back again. Any opinioins or experience?

[Alfa38User]

Thanks for the information and sorry I didn't get back before. I heard from Coleman and they said I can't use that thermostat because it is a 24V thermostat and I have a 12V air conditioner. After reading the responses here I am wondering if they are correct or just want to sell me a thermostat. Is this correct? Does the thermostat actually operate off of the 24V or does it operate off of the battery power? I thought the batteries provided the power to control the thermostat and it would handle up to 24V. Otherwise why are the batteries there and why does it not work when they are dead? I just don't want to cut all the wires off of my old thermostat and then have to put them all back again. Any opinioins or experience?

If you purchased a home type thermostat it is quite possible that it requires 24V A/C, not 12V DC. Many home thermostats installations have a small transformer that is mounted near the furnace to supply the 24V A/C or the perhaps the furnace circuit can supply the required voltage. If you did not purchase the Hunter model described in the link given in the post above, then all bets are off .....

The older mechanical thermostats do not require any power supply but simply rely on the temperature to close a mercury switch that closes or opens a contact to send whatever voltage the air conditioner or furnace has supplied back to the unit to turn it on or off. NOTE: This is NOT the way your original expensive RV thermostat works and probably cannot be used for a substitute in this case.

The batteries in the thermostat (if that is what you are referring to) are to maintain your setting on a programmable thermostat should the home suffer a power failure.

This post has been edited by Alfa38User: Jun 25 2009, 04:05 PM

[javaseuf]

"The batteries in the thermostat (if that is what you are referring to) are to maintain your setting on a programmable thermostat should the home suffer a power failure."
Not really acurate. The batteries do more than just this.

I work at an HVAC wholesale house and sell just about every thermostat made.

The batteries in a thermostat don't just maintain the programing. They power the digital display as well as the switching relays and circuitry. This is why many thermostats can be removed from their sub-base and be programed without the powered sub-base. Battery powered.
When purchasing a digital thermostat for RV use, be sure to purchase one that is battery powered, NOT hard wired or "power-stealing". The battery powered ones don't require 24-volts to operate.

I used a White Rodgers touch screen with auto change-over from hneating to cooling. It has been installed a year and hasn't needed the batteries changed yet.

BTW, Coleman was wrong. You don't need 24 volts or 12-volts for that matter, to power a residential digital stat that is battery powered. These thermostats are doing nothing more than acting as a switch for your wiring.

This post has been edited by javaseuf: Jun 27 2009, 06:19 PM

[Emery Nash]

I did this awhile back with different thermostats. one for the bedroom and one for the living room area with the heat pump (that makes it a little different). I documented my thinking and installation process with some cautions, conversion charts, pictures and additional info.

I hope this is of some help.

This post has been edited by Emery Nash: Jun 30 2009, 10:41 PM

[Asawang]

Thanks for all of the information. I did purchase the Hunter thermostat mentioned above. That is why I was pretty sure it SHOULD work on my 12V air conditioner and confused when Coleman said it wouldn't work. I think I will try changing it out soon if it will cool off enough that I don't die from the heat in the time it takes to change the thermostat. I hate the heat. You can always add another layer of clothes if you're cold but you can only get so nekkid when it is hot. I guess I shouldn't live in Houston.

[Alfa38User]

"The batteries in the thermostat (if that is what you are referring to) are to maintain your setting on a programmable thermostat should the home suffer a power failure."

........

Not really accurate. The batteries do more than just this.

I work at an HVAC wholesale house and sell just about every thermostat made.

The batteries in a thermostat don't just maintain the programing. They power the digital display as well as the switching relays and circuitry. This is why many thermostats can be removed from their sub-base and be programed without the powered sub-base. Battery powered.

...Snipped

You are correct of course, I did not think of it in that way. My home thermostat operates exactly as you say....

Thanks for correcting my mis-statement

This post has been edited by Alfa38User: Jul 2 2009, 12:11 PM

[SWharton]

We have been attempting to replace our Atwood thermostat with either a Hunter 42995B or a Ritetemp 6020. We have researched this on the internet and decided on to try these. Our current thermostat(Atwood 2h2c) has ceased to function with the A/C, furnace is OK.

What we have:

Atwood 2-stage furnace model 2334
Atwood 2-stage furnace digital thermostat 2h2c
Duotherm A/c model 57915.522c

Sage:

With either thermostat we can get the A/C to work on one fan speed fine. We never use low but if needed we would just put in a toggle switch.

We have never been able to get the furnace to work on either thermostat, works fine on the old Atwood.

Many people have done this based on the internet but no one mentions a 2-stage furnace.

Any ideas on next steps?????

We are considering 2 thermostats at this point: one for the A/C and one for heat.

Thanks,

Tom Wharton

[Rif]

Chris -- I think most of us missed this new question in an old thread. As for the furnace thermostat there is no problem moving it anywhere you would like. Of course it should be on an interior wall for best performance. You can replace the standard thermostat with a digital one. Most any digital type will work.

I don't know about the A/C without knowing what kind of thermostat you currently have. If it is the 4 or 5 button Climate Control Duotherm digital type with a phone connection in the back that runs to the unit on the roof I don't think you can change it out. The digital Duotherm thermostat is actually a computer that "talks" to the unit on the roof. You can certainly move it if you would like. It's just a matter of locating the wires and rerouting them to a different location.

This post has been edited by Rif: Nov 20 2009, 08:00 AM