HOW-TO: Dometic analog to digital thermostat replacement (pic heavy)
I recently did a Dometic analog to digital thermostat replacement and want to share the install. It was an easy install once I got the old control box out and organized the wires.
First, turn off the main breaker and the battery disconnect to cut all power to the AC unit. There is a 12 volt supply to the control box, so be sure to kill all 12 volt power.
The digital control box(right) is smaller in size than the analog box(left), but resides in the same brackets.
Analog
Digital
Cut the tstat wires, 12 volt wires, and heater wires. Unplug the AC control wire bundle, freeze sensor, and disconnect the 110 volt supply. Remove analog control box.
Remove the old freeze sensor and replace with new supplied sensor.
New(left) and Old(right)
Press new sensor into fins one inch from bottom (I put mine on the lower right looking toward rear of RV) and gentle bend fins around sensor to hold into place.
Connect the 110 volt supply to the digital box, matching wire colors and using wire nuts.
Find the two heater wires and attach the supplied spade terminals. The heater wire in this RV is a two wire cable consisting of a red and white wire.
Affix the digital box to the bracket on the AC unit with supplied screws.
Plug in the AC control wire bundle
Plug in the heater wires
Plug in freeze sensor.
Remove analog tstat
The digital tstat only uses three of the seven wires of the tstat cable. I choose red, white, and orange to match the color wire at the control box.
Connect the three wires.
Red: 12 volt positive +
White: 12 volt negative -
Orange: Common or communication
Before attaching tstat to the wall, be sure to cover hole is wall where the tstat cable protrudes. This will keep hot air for escaping wall cavity and give the tstat a false reading. I used some insulation and covered with foil tape.
More on next post.........
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2018 Refection 311BHS
2011 Wildcat 32QBT (SOLD)
2006 GMC 2500, Airsafe 20K hitch, Air Lift Loadlifter 5000 air bags with Air Lift WirelessONE compressor, EFI Live
Hey Cap, they don't show up in the thread. go to edit, then to advanced, then down below the text box you will see "Additional Options" and "Manage Attachments". Upload your images using it. I have found that if you use the insert image box you need to provide a URL address, but when you copy the address from your online library, the address is an HTTPS and due to this will not show up.
I was wanting to upgrade to the digital thermostat but not any more if it is that complicated. I did the replacement for a Coleman, they have a direct replacement,wire for wire took maybe 15 minutes.
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2005 Cedar Creek 30RLBS/TrailAir Hitch/ MORryde 7K IS/Disc Brakes/ PI PT-50 EMS/ RV Flex Armor Roof
2015 RAM 3500 DRW 6.7 Cummins 3.42/ Garmin 760RV
40 Gal TransferFlow fuel tank/ TST 507
Amateur Radio W5CI 2019 Days Camping 25
2020 Days Camping 7
Not totally sure what you're doing, but it seems way more complicated than it needs to be. Most of us remove the wires from the analog T-stat and move them to the digital t-stat. End of story. But maybe you've got one of those weird systems?
If old one has 2 fan speeds and new does not, add a SPDT switch to chose fan speed.
Here's what swapped for my Coleman-Mach to a Honeywell.
This is for a Dometic AC unit. I know a Honeywell tstat will work on a Coleman, but don't know on a Dometic. I like the how the Dometic digital tstat automatically switches fan speed based on set temperature.
__________________
2018 Refection 311BHS
2011 Wildcat 32QBT (SOLD)
2006 GMC 2500, Airsafe 20K hitch, Air Lift Loadlifter 5000 air bags with Air Lift WirelessONE compressor, EFI Live
Are the pics thoughout the post or all at the end? I meant to post a pic with a description. If the pics all show at the end with the icons throughout the post, let me know how to fix.
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2018 Refection 311BHS
2011 Wildcat 32QBT (SOLD)
2006 GMC 2500, Airsafe 20K hitch, Air Lift Loadlifter 5000 air bags with Air Lift WirelessONE compressor, EFI Live
2X Henboy. Seems much easier. I did that on my 2004 All American Sport. Just added a SPST switch to get Hi Fan. But Thanks for the info. Cap. looks like you did a great job.
Are the pics thoughout the post or all at the end? I meant to post a pic with a description. If the pics all show at the end with the icons throughout the post, let me know how to fix.
Capt: There's a way to do it, but I don't know it.
I recently changed my analog thermostat to Dometic's Digital Comfort Control Center (CCC). As you expalined, the change over was relatively easy, however, I did run into an operational problem. The wall cavity behind the thermostat is very warm compared to the cold air inside my motorhome - the end result is that moisture forms on the face plate and on the PC board. When this happens, there is a short, and the thermostat looses the communication link with the AC units. To solve this problem I sprayed some Window and Door Spray Foam into the cavity and placed a thin piece of sheet foam between the wall and the PC board. So far, it seams to have solved the problem.