Replacing Front A/C

[jwsroy]

I have to replace the front A/C on our 2005 Monaco Knight.  The fan motor has gone south and after a three month back order I finally got a replacement but no one can get the old one out without tearing up the works.  These are the original units on a coach used full time for all 16 years and corrosion and the elements have taken their toll.  Both units are Duo Therm Penguin low profile heat pump and A/C units.  I have a couple of questions.  I seem to be able to find both the new Dometic Penguin II units as well as their higher profile Brisk Air units.  My current system has the two A/Cs and the two furnaces controlled by a single thermostat.  Two temp sensors, one in front one in back.  Everything interconnected with telephone cord type wires.  I had the five button CC thermostat, but recently replaced it with a Micro Air unit.

I have been doing some internet research, which not surprisingly provides more questions than answers.  The consensus seems to be that putting a new unit online with a legacy unit 16 years old requires replacement control board(s), new thermostat and, depending on who's providing the info, new wiring.  If all that is true it almost makes sense to just proactively replace both units since it is probably just a matter of time before the back one gives out too.  We are full timers and spend a lot of time in the desert, so the units get a work out.  So my first question is whether anyone on the Forum has done a single replacement of an older Dometic and what issues they had to contend with.  Also any thoughts regarding just doing both units at the same time.

The second is whether anyone knows what the pros and cons of the two primary Dometic units, Penguin II and Brisk Air.  Both are available with heat pumps, both available as 13.5 or 15 BTU.  I think both can be used with a ducted air system like I have in our coach.  I don't really care much about high or low profile, we don't go anywhere that few inches will make any difference.

Appreciate any thoughts pertinent to my situation.

Thanks

Roy Holt

2005 Monaco Knight

2017 CMax Energi   

[KevinH]

I changed out my front AC unit. First thing I did was get the model number off the unit.I called Dometic to find out what model I needed to swap it out with. They gave me the model number and told me that my five button thermostat would not work unless I changed out the board so I went with the new thermostat. I also went with an AC only because we never use the heat pump option on the old one. I also got the model number for the drain pan and purchased that also.           Then I started to research everything online .It was basically an easy swap out.           So I order the unit on Amazon with the drain kit and the new thermostat. When I receive the unit the first thing I looked for was instructions there were none. I called the seller and they told me that’s how it came from Dometic no instructions no hardware.      The drain kit did come with instructions so I started with that. I installed it then I put the unit on the roof and hooked up all the wires the exact same way they were hooked up on the old unit there are two yellow,two blue, one red one black.the two yellow are not used. I hooked up the other four wires. there are two 

Telephone cable connections. I only needed one because my Front units is a one zone system for the front of the coach and then hooked up the new thermostat temporarily. Then I hooked up the main power basically the same way the old power on the old unit was hooked up.Everything worked properly.  I have an aqua hot system and it was not showing up on the thermostat. So at this point I figured I needed some instructions and called Dometic. they emailed me instructions. after that it was pretty easy other than making sure you line up the ductwork. 

[vito.a]

I replaced one of our Duo Therm Penguins.  I had to also order a conversion control board because on our coach the two A/C's are controlled by one 5-button thermostat.  The old 5-button Comfort Control thermostat is not compatible with the new A/C without the new conversion control board.  And the new programmable thermostat will not work with our older A/C.  

The new units utilize the same wiring (RJ11 telephone cords).  

The Penguin is similar to the Brisk Air with the compressor turned sideways.  This makes the units lower (I think 2").   They work identical and both are available in 13.5k and 15k BTU.  If you live in the desert as we do I would encourage you to go with a 15k unit.  

There is also a new designed Dometic A/C unit (Blizzard NXT) available but I could only find it in black.  

I purchased my unit from PPL RV parts department.  They are very knowledgeable and have great customer service. 

https://www.pplmotorhomes.com/parts/rv-appliances/air-conditioner/air-conditioners-coleman-dometic?facetValueFilter=tenant~manufacturer%3adometic

I installed the A/C myself.  Once you get it on the roof there are only four bolts holding it on.  

There are small dip switches on the control board that tell the system if you have a furnace connected and what zone as well as a few other things.  These must be set the same as the old unit.  

Detailed thread: http://www.irv2.com/forums/f115/replacing-a-dometic-ac-heat-pump-on-a-monaco-coach-405503.html

Hope this helps.  

Edited September 8, 2021 by vito.a

[Walker]

I recently was in a similar situation.  I decided to replace both units and use the new thermostat.  I like the new thermostat better.  I went with 15k blizzard nxt heat pumps.  They work well and are quieter than the penguins they replaced.