Adding an Accurate Thermostat to your Coach...

[sandpirate]

Heating and cooling thermostats that come with most coaches are very basic in nature, one big gripe from me is that there is no display that gives me an accurate readout of the coach temperature, and without that I will never know just how accurate the thermostat is to begin with. So why not add a residential digital thermostat to your coach?

Hunter builds a great, inexpensive thermostat with an easy to read Indiglo backlighting function and programming capabilities for around $25, and best of all, it’s available at most Wal-Mart stores.<O</O
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Snap a digital photo of your current thermostat wiring before you disconnect any wires on the original stat to insure that your colors land correctly on the new stat.

To make the switch from the Duo Therm stat to the digital Hunter stat:
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If there is not an existing jumper(connector) between RC & RH terminals on the Hunter stat, then add a wire to connect the two terminals.
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Duo-Therm stat -- Hunter stat
+7.5 (red) -- not used
Cool (yellow) -- Y/O
FUR (white) -- W/B
Hi Fan (blue) -- G
Fan (brown) -- G
GND (green) -- RC & RH(jumper)​

With this Hunter thermostat configuration the a/c function will always be on high fan.

 

[jmgratz]

It there a way to wire it where you can change the fan speed?

 

[jimtoo]

Hi sandpirate,

Thanks for posting your conversion of the a/c thermostat to digital. It has been used by many people for the last several years. Also by adding a small toggle switch or slide switch to the case you can choose to run fan on high or low, depending on switch position. The mod works great, especially with the high/low switch added in either the brown or blue wire. There is a really good instruction sheet on here somewhere.

Jim M

 

[JohnDar]

Here be the basic instructions. So simple even a caveman could do it.

http://www.modmyrv.com/2008/07/14/rv-digital-thermostat

Did mine last year, some time, and it works great. I did find that running the A/C for several days on low fan did ice up the unit. Switching to high fan eliminates that.

 

[sandpirate]

It there a way to wire it where you can change the fan speed?

Yes there is, you can add a two position micro switch between the blue and brown wire. I live in Phoenix, so if it's warm enough for the a/c to be on we want the fan to provide as much airflow as possible.

 

[porthole]

Since it comes up again - has anyone found a digital thermostat that will actually work with a heat strip installed as an aftermarket?

I have the Dometic digital that is supposed to work but it does not and Dometic will not offer tech assistance to the private field.

 

[sandpirate]

Since it comes up again - has anyone found a digital thermostat that will actually work with a heat strip installed as an aftermarket?

I have the Dometic digital that is supposed to work but it does not and Dometic will not offer tech assistance to the private field.

The Hunter thermostat should work fine in your case, the pin marked W/B on the hunter stat is for a Heat relay.

 

[RoadJunkie]

I believe this is the model I used: http://www.hunterfan.com/Products/T...ay-Sat-Sun-Programmable-With-Backlight-44260/

Walmart also sell it and it adds programing, Indigo back light, and some other energy saving features. I only used the high fan speed on this unit.

 

[sandpirate]

I believe this is the model I used: http://www.hunterfan.com/Products/T...ay-Sat-Sun-Programmable-With-Backlight-44260/

Walmart also sell it and it adds programing, Indigo back light, and some other energy saving features. I only used the high fan speed on this unit.

That's the one I'ved always used, you should be able to get it in the store for no more than $25.

 

[porthole]

The Hunter thermostat should work fine in your case, the pin marked W/B on the hunter stat is for a Heat relay.

So what does W/B stand for?

Heat strips are controlled by the low voltage thermostat. I would guess that a unit using a heat relay is a line voltage control.

 

[cgrn59]

I installed a Honeywell digital using the same configuration that you posted. putting brown wire to "G" give low fan, but putting blue wire to "G" gives no fan. putting bothe wires on "G" gives high fan. I contacted Domectic and they said supplying voltage to hi and low fan will wreck it. What gives? why does the blue wire not give me high fan? Can you clarify this? Maybe I need a Hunter digital??

 

[RoadJunkie]

I'm curious as to their technical definition of "wreck it". Will the configuration "wreck it" immediately, or over a period of time?

 

[cgrn59]

How did you hook yours up? blue and brown wire togther is the only way I get high fan.

 

[katkens]

How did you hook yours up? blue and brown wire togther is the only way I get high fan.

The blue and brown works fine hooked together. I did it this way on my Hunter Thermostat , going on 4 years of trouble free operation. I could'nt see adding a switch for both low / highspeed fan, since I only use the high speed......Kenny

 

[caissiel]

Thanks for the instructions
I replaced the thermostat with a 1 week honeywell model.
Same thing it did not run the fan by connecting the Blue wire so connected the brown for now.

It seam to work as the old thermostat, with continues/auto fan on AC and nice furnace controls.
Set at 70 it starts at 69 and stops at 72 by the time the furnace cycles thru the cooling cycle. The furnace runs much less then before.
Its been in the mid 40's outside here since I installed it.

Now I don't have to get out of bed to lower at night or get out of bed to raise the temperature again in the morning.

Well worth the cost for the comfort.

similar unit at Lowes
http://www.lowes.com/pd_11408-74493...currentURL=/pl__0__s?Ntt=honeywell+thermostat

 

[porthole]

I've asked before, but since there are new people looking - anyone find a digital to work with an added on heat strip?

 

[lwmcguir]

Many of the heat strips aren't intended for continuous use, just a warmer. Might have to use a separate thermostat.

 

[caissiel]

Will have to use a seperate line voltage programable theremostat.
That is if the line can be access to connect the thermostat in series with the heat strip.

 

[porthole]

Heat strips are unique in that they use a low voltage control, not line voltage.

 

[caissiel]

My mistake sorry
Then a seperate low voltage unit would do.