Digital Thermostat Installation in RV HVAC Systems
LES ADAMS ARTICLE FOR WIRING HUNTER DIGITAL THERMOSTAT
INTO DOMETIC A/C AND ATWOOD FURNACE
There was a thread on another BBS by Alan Paskey about his installation of a Hunter Digital Thermostat for his A/C and heat... I have been wanting to do this for some time now and finally got around to going over to "Wally World" (Wal Mart) and buying the thermostat and "getting off my duff" and installing it!!!
I installed it yesterday... Unfortunately, I have a Dometic (Duo Therm) ducted A/C unit and Atwood Furnace and Alan Paskey's unit was a Coleman... His wiring documentation DID NOT work for me... I spent the better part of the day figuring out how the Dometic contact closures worked and then another few hours doing the same for the digital thermostat and marrying the two together...
The digital thermostat is a Hunter - Part #42995 and is $19.95 at "Wally World" (Wal Mart)...
The advantage to the digital thermostat is tighter hysterisis (+/- 1 degree of temperature change
yields "turn on" or "turn off"), a digital temperature readout, and no guesswork about where
temperature is set for your particular "comfort zone"...
The Hunter Thermostat runs on 2 AA pen cells which are NOT supplied... I would suggest you carry spares as well, for if the batteries go dead, so does your thermostat (AND A/C and Heat)!!!
The following documentation will apply ONLY to my particular Dometic type A/C unit and Atwood furnace although it should work on other similar Dometic systems and possibly other manufacturers as well... As previously mentioned,
Alan's wiring documentation (his was a Coleman) DID NOT work on my unit, so bare in mind that some wiring changes may be necessary to make the Hunter Digital thermostat function properly with your particular system if they are different than the two referenced within this article...
Duo Therm | OEM Wire Color | Hunter stat terminal |
(original) | used in trailer |
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Ground | Black or green | "RC" |
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Fan | Orange or Tan | "G" |
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Cool | Yellow | "Y" |
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Ground | Black or Green | "RH" |
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Furnace | White | "W" |
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High Fan | Blue | Thru SPST switch |
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| to "G" (Tan) |
Red | +7.5 volts DC | not used |
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