If you're interested - - see Part 1 at "
Adding a Thermostat to Dometic Penguin II Air Conditioner"
This is how I added a digital thermostat to control the furnace and air conditioner in my Bambi Sport 16RB. It works almost perfectly! The thermostat does what you expect – turns the furnace on and off, turns air conditioner on and off based on the heat and cool settings. It is wonderful to have the trailer at the temperature I want.
What makes it “almost perfect”, is that you have to select either Heat Mode or Cool Mode on the thermostat. It would be perfect if you could simply set a heat temp and a cool temp and the thermostat would figure out which appliance to turn on. Oh well – First world problem. This is a huge improvement over than the horrible Dometic analog furnace thermostat that came in my Airstream.
My 2018 16RB is a non-ducted Dometic Penguin II Air Conditioner “jet engine". Works ok, but damn it's loud. I wanted to hook it up to a digital thermostat because the lousy little turn-it-a-little-colder, turn-it-a-little-warmer knob on the AC is a piece of crap. I wanted a thermostat so I can set a temperature and leave it alone. I also wanted the thermostat to control the furnace - replacing the cheap, shitty Dometic craphole analog thermostat.
The parts I purchased ...
Thermostat - Honeywell TH1110DV1009 Pro 1000 .
Battery powered. Has Heat mode and Cool mode. It has an interesting feature where it won't turn on the AC until the AC has been off for at least 5 minutes - this is to protect the compressor. The thermostat's heat mode will control the furnace.
Relay - 12VDC coil, 277VAC 30amp contacts, normally open.
5 feet of 2 wire 20 gauge wire. Like lamp cord but thinner.
2 feet of 14 gauge stranded wire
A few wire nuts (I used
Wago connectors because I like them, typical wire nuts would work just as well)
4 “Flag” style 1/4” female spade connectors (2 for 20 gauge wire, 2 for 14 gauge wire)
1 rubber grommet 3/8” OD x 1/4” ID x 1/16” groove
1 foot of 1/2” flexible, split wire cover/protector
1 foot of 1/2” channel wire cover/protector
Disclaimer – Honestly appraise your own skills and knowledge. This is a medium difficult installation that took about 2 hours to complete. If this installation exceeds your abilities, stop, do not proceed. These notes roughly cover what I did. It worked. I don’t know if you can do this. I don’t know if it will work on your particular RV. I am not a professional. I’m not responsible for the consequences of your actions. I’m not responsible for any error, omission, lack of clarity, nor confusion in these notes. This installation has not been submitted to, reviewed by, nor approved by Dometic, nor anybody else. But it worked for me.
I’m a knucklehead that knows just enough to get myself in trouble. But, I’m pretty good with my hands, using tools, and fixing stuff around my house. I’m comfortable with electrical wiring, and the disassembly/reassembly of things. Proceed at your own risk. Enough said.
These are not step-by-step instructions. They’re generalized, rough notes to give an idea of what I did.
Before and After wiring diagrams …..
Installation Notes in 2018 Bambi Sport 16RB ….
Preparation
1. DISCONNECT ALL POWER FROM THE AIRSTREAM – UNPLUG THE SHORE POWER AND TURN OFF OR DISCONNECT THE BATTERIES.
2. Remove Air Conditioner’s air distribution cover (about 10 screws), pull off the 2 knobs.
3. Remove the metal cover where the 120VAC power wire connects to the Air Conditioner.
4. Disconnect and remove the cheap, shitty Dometic craphole analog thermostat. Then beat the hell out of it with a sledgehammer so it can never be used again! What a POS!
5. Remove the plastic housing on the inside of the closet that covers the wires to the thermostat and bedroom light switch.
6. Light in closet – remove lens, dismount from wall, disconnect from power wires.
The wire to the light is in a flexible, split plastic tubing that was loose in the closet. I drilled a 1/2” in the top of the plastic housing (removed in Step 5) and ran the plastic tubing up through that plastic housing.
7. Figure out how to route the 20 gauge wire through the top of the closet to the AC.
Mine had a tiny gap between the wooden piece above the closet door and the ceiling where I could fish the wire through. In the top of the closet, a bunch of wires run through a hole in the ceiling. I wanted to fish the wire through that hole to the AC. But failed. So, instead, I routed the wire tight against the ceiling.
12VDC Circuit
8. Mount the relay. See the picture for where I mounted it.
9. Run the 2-wire 20 gauge wire from the relay thru the closet, down the closet wall and thru the thermostat hole in closet wall. Leave lots of excess wire.
10. At the relay, connect wires to relay with female spade connectors.
11. At the light in closet, cut 1 (NOT both) of the 2 wires. Connect 1 end with the -12V power wire, connect the other end with the other +12V power wire. It doesn’t matter which wire is connected to which.
12. At the thermostat, REMOVE AND DISCARD THE RC to R JUMPER. Insert 1 wire in the Rc connector, insert the other wire in the Y connector. It doesn’t matter which wire goes in Rc or Y.
13. The furnace wires connect to R and W.
14. Position and mount the thermostat backing plate. I wanted to position the new thermostat to cover the screw holes from the old thermo-****. To make this happen I had a grind a little channel in the wall to allow the wires to bend and fit into the new thermostat.
120VAC Circuit
15. Disconnect the black 120V wire from the black air conditioner wire. Leave white wires connected.
16. Run two 14-gauge wires from relay to that little metal box where the 120V power connects to the air conditioner.
17. Connect wires to relay using female spade connectors.
18. Wire nut 1 wire to the black hot 120V wire. Wire nut the other wire to the black wire from the air conditioner.
Finish
19. Recheck everything to ensure good solid connections, safe wire routing, etc.
20. Reinstall metal cover at power source to air conditioner. I filed a notch in the side of the cover, slide the 2 new wires through a rubber grommet, installed the cover with the grommet in the notch to protect the wires.
21. Reinstall everything.
22. Cover any exposed wire in flexible, split wire protector or channel wire protector.
23. Double check everything to ensure accurate, safe installation.
24. Connect/turn on batteries and shore power
25. Test thermostat to control furnace
26. Using knobs on air conditioner, turn air conditioner to ON and full cold. Test thermostat to control air conditioner.
27. Jump up and down in joy and yell “Whoo Hoo”.
28. Wrap up the old thermostat you smashed in Step 4, mail it to Airstream and tell them to quit putting a shitty $5 product in these crazy expensive trailers.
Linear Mode
