Community Forums

Arbogaster · 02-18-2019, 07:48 AM

Greetings ! ! !

I swapped out my factory original DuoTherm unit in the front of my 36' Windsor yesterday. I went with a 15,000btu Heat Pump Dometic Penguin II. My old unit is still in the back of the unit and will be swapped out before summer the new stat wont talk to it without a retrofit board. The old unit came off rather easily. I dropped the new one in its place. The old unit had (3) 120VAC wires in a metal box. I reconnected those. on the low voltage side the old unit and new unit use the phone cable communication wire. I reconnected those. The old unit has a white wire with a quick disconnect which looks like a freeze sensor that sits in the coil. I reconnected that. I also connected the two blue wires which go to the furnace. All I have left on the new AC side are the black and red 12 volt wires and some yellow "load shedding wires". My old unit did not utilize any 12v power so on my coach there is no 12v available. The old unit had the same wires in its harness but all those wires were capped off. The instructions from Dometic appear to suggest that I need to get 12v to this unit. I have not done this yet.

I installed the new thermostat in the back. I did not touch the wiring on my old unit in the rear. The new therm recognizes the front as Zone 1. I can turn the fan on and turn the furnace on with no problem. I tried to turn on the heat pump and it kicks on after a 2 minute wait but then it kicks off within about a minute. It appears to be blowing slightly warm air and I can hear the compressor humming. I'm not sure what to look at next. I found a diagnostic sheet on the thermostat. Maybe that will give me a clue??
The only DIP switches set on this unit are heat pump and furnace.
Anyone else run 12V power to a new AC install where 12V did not exist before???

Seems odd. . . .

Any other wisdom out there is greatly appreciated. I have a buddy who is an AC tech for many years. I know he is willing to help but the RV part of it might stump him a little.

THX guys & gals!

vito.a · 02-18-2019, 03:32 PM

I'm trying to understand. What year is your Windsor?
You installed the new 15,000 btu heat pump on the front.
You installed the new programmable CCC2 thermostat in the rear?
Do you still have an older AC unit in the rear that will not talk to the new thermostat?

The older units used 12v on the reversing valve to activate the AC (they were normally in heat pump mode). The new units are normally in AC mode and then use 12v to activate the heat pump reversing valve. I'm guessing you do not have 12v to the new unit to activate the reversing valve.

Usually, the front unit is the master and the 12v wires provide power to it and the rear gets 12v from the RJ11 phone cord daisy chained from the front.
I guess yours could be wired with the rear as master.

I installed a new 15,000 heat pump also but I used a conversion board so mine would talk to the older 5 button thermostat. IRV2 member bruveisla used the new CCC2 thermostats on his install and is very knowledgeable.
Send a PM to bruceisla. Select private message in the upper right corner and send him a PM (private message).

mlh2013 · 02-18-2019, 06:43 PM

Vito.a, I sent you a PM I hope you don't mind, didn't want to hijack this thread

Arbogaster · 02-19-2019, 06:50 AM

My Windsor is a 2002. I installed a 15,000 Heat Pump ( Penguin II) in the front only. Old one still in back for now.

New CCC2 in the rear. Control RJ-11 cable still routed through the rear AC but controlling the front AC just fine (at least I think it is)

I ran the diagnostic from the stat last night. The compressor, fans, dip switches, temp sensors, and all other things seemed to work fine. Fired up the unit on Heat Pump last night and this time it ran for about 5 minutes before kicking out. the air it blew was kind of warm but not that warm. Once it kicked out it seemed to want to try to restart after a few 2 minute pauses but it would not hardly get started before kicking out again.

My next move is to temporarily run a 12v wire to the unit as called for in the installation instructions. I can't imagine what this 12v is needed for but it calls for it in the Dometic book. My old units had provisions for 12v wires but neither of the units had been hooked up to 12v and there is not a 12v wire available in the ceiling. If the 12v wires are the answer I'll need to find a way to cleanly route some through the ceiling at some point. #FUN!

Any other thoughts are appreciated.

THX,

Eric

vito.a · 02-19-2019, 03:08 PM

I'm thinking your old unit was not a heat pump and did not require 12v for the reversing valve. Your new heat pump needs the 12v for the heat pump reversing valve.

Found Bruce's post in an earlier thread. Hope this helps.
http://www.irv2.com/forums/f258/dome...-430640-2.html Post #20
2 blue wires are for the furnace .... normally only on front unit unless you have more than one furnace.
red and black are normally 12vdc and normally are not used on the rear unit.
RJ11 connector is the communication cable and usually goes forward to front unit and plugs into the board on the front unit .... communication is a daisy chain .... CCC2 to front unit then front unit to rear unit.

If your coach does not have 12v wiring to this location, you can use a 120 to 12v power supply. Wire the power supply to the three AC wires inside the AC junction box.
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
I used this power supply to run a 12v ceiling fan.

Arbogaster · 02-20-2019, 06:52 AM

I can easily rig up a temporary 12V and see if that works. Funny thing is in the diagnostic mode of the CCC2 it has a setting to test the reversing valve. I heard an audible click when the reversing valve "fired" in test mode . . . but it may have just been a relay closing. The other weird thing is the air coming out of the AC and into the coach was kind of warm before it kicked out. I would think if the reversing valve did not work it would have been essentially running in AC mode. Its for these reasons I had myself talked out of the 12V issue.

I REALLY appreciate you taking the time to look over my issues. I'll report back on how things worked out.

Cheers!

Eric

jacwjames · 02-20-2019, 07:19 AM

The reversing valve default so heat mode.

I had the wire that provided power to the reversing valve short out. The AC would blow warm air. Once I figured out what was going on I fixed the wire, made sure it was secured so it wouldn't short out again, and fired up the AC unit, that was 5 years ago and the unit is still working.

I am watching this post as sooner or later I may have to deal with the same issue.

Arbogaster · 02-22-2019, 06:34 AM

OK . . .so apparently the lack of a 12v power and ground WAS the issue with my AC not acting right. I hooked up a temporary 12v wire from my Power Probe tool and got 12V from the Cig Lighter on the dash. Fired the Heat Pump up and ran for a solid 15 minutes with no problem.

I did try hooking up a 12v power supply which was powered by a 110 outlet in the RV. For some reason the thermostat could tell the difference between that and the cig lighter and decided to give me an E1 error. One of the reasons for E1 is "dirty 12v Power". My thermostat paperwork said to make sure 12v came from the battery. Once I had 12V hooked up from the battery everything worked fine.

Now I have to figure out how to route some 12V wires through the ceiling to make this all work. I'll do some searching and start another thread for that I guess.

Cheers!

Eric

vito.a · 02-22-2019, 11:05 AM

Eric, maybe you can route a 12v wire from the other AC through the duct to the new AC.

veraken · 02-23-2019, 08:04 AM

Don't know what your set-up is, so this just FYI.

We replaced our T-stat with a new Dometic CCC2 unit. When we did, we had a problem. The thermostat is mounted on an outside wall and there is a small cavity behind the thermostat where the wires are run. In the summer heat, the high temp in the wall meeting the cool air inside, created condensation on the thermostat's PC board which caused it to short out. To solve this I used low expansion spray foam in the wall and a sheet foam on the back of the PC board. So far, everything is fine. If not I will have to relocate thermostat to an interior wall.

Arbogaster · 02-24-2019, 03:32 PM

My stat is on an interior wall closet. I don't think I'll have that kind of problem. As for running 12V electric I'm curious to see what I can find to route through the ceiling with nearby stereo speakers and other things. If I can get 12V power to one of the units I may just cheat the system and feed the other one through the duct work.

Cheers!

Eric