For those of you that want to personally replace your older ducted Penguin Heat Pumps (HP) here are my thoughts on my DIY on my 2007 Newmar MADP 4528.
1. The front #1 HP was operational, but never seemed to deliver the air flow of the other units, even on high fan position. #2 HP mid coach had a frozen compressor. #3 rear was intermittent, stick reversing valve. Finding out what was wrong took me a few days on the roof and lots of internet searching on the subject. I am a retired mechanical engineer with a decent electrical background. I can see where it takes a quality RV tech to diagnose the RV systems and do the correct thing.
2. Once it was determined that 2 HPs needed replacement we elected bite the bullet to do all 3 units and update the 5-button Dometic thermostat to the 12-button CCC2 thermostat. The current Dometic low profile HPs require an adaptor board to work with the older 5-button thermostats and while replacing only the #2 only was an option, I felt it made more sense to do it all.
3. After researching three of the Dometic Penguin II high capacity Heat Pump 651816.CXX1C0 were bought from PPL out of Texas. PPL had them on sale for $999 each with decent shipping rate.
4. Called Newmar and found out that the only additional Newmar part required was a bent L shape gasket ( Newmar Part Number 52715) to separate supply air from return air. It mounted within each 14" square Dometic gasket on the underside of the Penguin.
5. I got a shrink wrapped pallet from PPL within a week, excellent. Now how to get the old ones off the roof and the new ones up there. I rented a hand crank material lift with a 600 lb capacity and a 18 foot max lift. It folded up and with two person easily went into the standard bed of a ford pickup. $150 per week. Turned out to be a very good decision on the lifting up and down. See attached picture.
6. Elected to replace the #2 unit first, as it was the one totally dead with frozen compressor. I made a long temporary RJ-11 Communication cable, not the usual telephone cable, different pin-out, to connect #1 and #3 HPs together. Set the dip switch on the old #3 HP control board so it thought it was zone #2. This was to maintain heating and cooling while replaced #2 HP.
7. Turned off the power distribution panel breaker for # 2 HP, tested for power, labeled wires and took pictures on cell phone. The only somewhat difficult part was the removal of the four lag bolts that Newmar uses to mount their roof top units. Required a 1/2 inch drive 6-point socket and a long flex handle. I looked at the lag bolts when all four were out and there was one with a very worn tip threads. Went to Home Depot and purchased 9 of the shorter ones and 3 of the longer style. After lifting and wiggling I got it to lift off. Set aside the old HP and thoroughly scrapped and cleaned the area. Poured water in the two condensate drip pockets, underneath the HP, installed in the roof. For the ones not draining well, I took apart and cleaned the condensate drip pockets in the roof. The drip pockets have clear vinyl tubing that goes to a PEX pipe that drains at the rear of the coach, each side. You will need to blow that tubing out and not kink the tubing when re-installing. Wish Newmar had installed plastic tubing with nylon thread reinforcement to prevent kinking. For some unknown reason all the ones on the driver's side were clogged. I used non-leveling caulk on condensate pockets and silicone caulk on the lag bolts.
8. I got the DW up on the roof to assist me in positioning the new HP on the opening. Got her lined up and slowly drew down the four lag bolts till the foam pads at the four mounting position were one-half the original height. Installed power and did all the control wiring short of the RJ 11 communication cable. At this point set the dip switches for zone 2 and HP on the new control board and installed the cover. By the way the new Penguin covers are a vast improvement. The old flimsy ones would crack if you looked at them wrong. Thanks to Dometic for improving that part!
9. Installed the new CCC2 thermostat temporarily with tape next to the old one.
10. Removed #1 HP. Noted that the aluminum duct tape had pulled loose around the plenum and was partially blocking the supply air duct. Removed all the tape in the area, carefully cleaned and re-taped with a high quality low temperature rated aluminum duct tape. Also noted that Newmar had installed the high voltage Junction box partway into the return air plenum. Move it a couple of inches and plastic wire tied the Newmar wiring, in the area of the return air plenum, to minimize disrupting air flow. Between the taping, moving the J-box and wire tying the New HP had a much improved air flow at the front of the coach.
Wiring differences at #1 HP were a dedicated 12V dc feed and the Hydro-Hot (furnace) wiring. The two wires for the Hydro-Hot /Furnace are a broken circuit wire. The HP controller board has a relay that connects the two together to make a circuit. It makes no difference on how you connect the two wires to the HP control wiring. Set the dip switch for furnace. Then I connected the thermostat wiring from to # 1 HP, finished installing the new CCC2 thermostat, reset the thermostat and tested with only #1 new HP connected to thermostat. Thermostat picked up the new HP and furnace capability. Reset the thermstat from the "Furnace" display to "Aqua." Something nice that Dometic added for owners of Hydrohot and Aquahot. 1/3 of the way done now.
11. Took off the cover of new #2 HP and connected the RJ-11 cable that runs to #1 HP. Reset the CCC2 again and it now showed two zones. Tested all functions and all was right with the world. 2/3 of the way done now.
12. #3 (rear) HP was more difficult due to flat rack mounted solar panels mounted over the HP. Turned out the New low profile Penguin II HP was about 1-1/4" taller than the older penguins. Had to lengthen the aluminum angle supports so there was about 1/8" clearance. Another problem I did not anticipate was the older wiring for the rear HP did not have a dedicated 12V dc feed. The new CCC2 thermostat requires it. Used a spare fuse position in 12V panel above mid toilet, removed fantastic fan and supply air, and using a fish tape I ran 16 gauge high temperature insulation stranded copper wire thru supply air duct to #3 HP plenum. Taped the 12v wires with aluminum tape to hold fast and seal penetrations. Labeled the spare fuse as HP#3. There was also Hydro-Hot (furnace) wiring like HP#1 in the front.
13. Through-out the installation I cut the old male RJ-11 cable ends off, installed new ends and tested each run for opens, shorts and pin-out errors. Used a Klein brand VDV Scout Pro 2 Tester Kit I got at Home Depot for about $80.
14. The new CCC2 12-button thermostat is easier to read, can automatically switch between Cool/HP/Aqua (furnace) as needed to maintain temperature. It even has a clock function that allows night set-back. Each zone's temperature sensor reading can be read out at the thermostat and you can compare that to the set temperature for fine tuning of the set-points. Dometic has a vastly improved it's thermostat.
It was quite a bit of work, but is doable for the RV owner who is comfortable with power and low voltage wiring and has a decent set of mechanical skills. Having a whole new HVAC system was worth it for years of trouble-free usage.
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