Skip to main content ↑ ↓
Topic: Dometic Duo-therm Penguin Issue (Read 1925 times) previous topic - next topic

Dometic Duo-therm Penguin Issue

Hello to all once again. This time I'm asking about AC units. I have a 1996 U320 with two Dometic Duo-therm Peguin AC units and the 4-button Comfort Control thermostat. Recently my front AC stopped working. Worked fine before a trip then when we returned the fan no longer works. Compressor turns on but the fan never comes on, whether in "cool" mode or "fan" mode. Haven't checked heat strip mode, but i assume the same. i took off the shroud and metal covers and there are no obstructions and the fan motor spins fine. Not quite as good as that for the rear unit, but still spins and freely continues after releasing.  I thought maybe this would be the capacitors, so I changed them. No change in behavior. After tinkering with it a bit and attempting to lubricate the motor shaft I had one instance where the fan spun for a second before stopping. Has not moved since during attempted starts.

I've been told this could be a bad control board, and i understand these are difficult to find. Does anyone have any comments on this, how i can verify the control board is actually the problem, and where i can find a replacement?

On another note, the rear AC unit works fine but for some time it has been doing a strange audible frequency change during operation. i don't know how to explain this other than it sounds like it periodically "revs up" and changes to a different sound frequency before returning to the normal. i don't see any signs of failure but maybe this is a warning of something to come...

Thanks

Re: Dometic Duo-therm Penguin Issue

Reply #1 –
Only  do the following if you know what do do around electricity. It can kill you either by electric shock or getting shocked and falling off roof.
Turn just the fan on with thermostat. Then go on roof and verify motor has 120 volts. If you do, then bad motor, if not, bad board.
2014 ih45  (4th Foretravel owned)
 1997 36' U295 Sold in 2020, owned for 19 years
  U240 36' Sold to insurance company after melting in garage fire
    33' Foretravel on Dodge Chassis  Sold very long time ago

Re: Dometic Duo-therm Penguin Issue

Reply #2 –
You might try pinging Jim Frerichs on the forum - he repairs the 4-button controls and might be able to help confirm that the board is the issue

Dometic 4 button thermostat repair
Learn every day, but especially from the experiences of others. It's cheaper!  - John C. Bogle

2000 U320 36' non-slide / WildEBeest Rescue
2003 U320

Re: Dometic Duo-therm Penguin Issue

Reply #3 –
I had an issue similar to yours.  What I found was the solder at a relay on the board was cracked in a couple of places.  I took a picture of the wiring, then removed the board, and re-soldered the relay legs back to the board.  Still working after five years.

This fix may work for you.

jk
Jack and Cathy
1992 U280 Unihome 36' Build #4034
Cummins 8.3 /  Allison MT647/ PacBrake
Apopka, FL / Barre Center, NY

Re: Dometic Duo-therm Penguin Issue

Reply #4 –
Thanks for the suggestions.

I have worked with Jim Frerichs previously on an Aquahot board, but i don't think the issue is the thermostat itself. If Jim fixes the control boards for the AC this could be a possibility. Thanks.

I will check the volts on the motor to confirm whether it is good or bad.

When you removed the control board to inspect and fix the solder what was the process? seems to me the board is rather hard to access, and you must get to it from inside and remove the unit mounting bolts and metal cover to get to how it is mounted. Maybe easy, just want to make sure. If you can elaborate on the process it would be helpful. The attached photos are what I'm seeing from inside.

Thanks


Re: Dometic Duo-therm Penguin Issue

Reply #5 –
You need to check the micro farad on the two capacitors. My original capacitors went bad and the fan wouldn't run. You have one capacitor that is a dual fan/compressor capacitor.  The whole thing can fail or just one side. Many good multimeters have a capacitor test setting.  I'm no AC guy but after attending a few YouTube tutorials I tested mine. The fan side was dead. Replaced capacitor and the magic reappeared. If you replace one, replace all three. It will save you time in the long run if they are original.

AC fan run capacitor
1998 36 foot U270 Build No. 5328 WTFE, 900 watts solar, Victron controller, B2B, bat monitor, 600 AMPH lithium with 2018 Chevy Colorado toad, SKP #110239, Motorcade #17781, 2021 Escape 17B for when Coach is broken down and campsites are too small, retired and full-timer since Dec. 2020. Part of RV family since 1963.

Re: Dometic Duo-therm Penguin Issue

Reply #6 –

We had problems with one of 2 Penquins on our U270.  The problem was diffrent (no cooling) but once we replaced both capacitors (with similar micro farad ones from Amazon) and the PTCR all was good.  the PTCR is a simple device that  allows max torque to the compressor (not the fan) so I would suspect and replace the capacitors first.  In our Penguin II we used these parts:

Run Capacitor (for compressor and fan)  $12.97
30 + 5 MFD Capacitor 370 or 440 VAC Round Run Capacitor for Fan Motor Blower Condenser in Air Handler Straight Cool - Heat Pump Air Conditioner - Furnace - Pool Pump - by The HVAC Genius
The HVAC Genius 30/5 uF 30+5 MFD 370V/440V Dual Run Start Round AC Capacitor...

Start Capacitor (for compressor only). $9.94
PTMJ88 - Packard Aftermarket Replacement Motor Start Capacitor 88-108 MFD 220 250 Volt
PTMJ88 - Packard Aftermarket Replacement Motor Start Capacitor 88-108 MFD...

PCTR Start Resistor for compressor $51.99
Motor Starter 10-amp (CERA-MITE 305C20) Replacement for Manitowoc 8505003
Amazon.com: Manitowoc ICE 8505003 PTCR 10 - amp Motor Starter Replacement :...

We also looked at YouTube for wisdom.  All this because no one here in central Texas fixes RV A/C....they just replace them for @$2k each.  The fan should run (just on fan mode without the compressor running) and if it doesn't then that is what I would focus on (fan motor test with multimeter, capacitors, board and thermostat). 
Good luck!

As an Amazon Associate Foretravel Owners' Forum earns from qualifying purchases.
Carl and Kathleen
Killeen Texas
1997 U270

Re: Dometic Duo-therm Penguin Issue

Reply #7 –

Thanks for the suggestions about the capacitors but that was the first thing i did. i didnt use the same ones linked by Carl, but i matched what was already in the unit (which was working for a long time before this happened). i don't have three caps, only two and a resistor. perhaps the resistor is bad? but the compressor comes on without issue. the only issue is the fan.

I used these. i suppose it is possible one of them could be bad, but assuming they are good:

Amazon.com: VEXUNGA 25/10 uF 25+10 MFD 370VAC or 440VAC Dual Run Start Round...
and
Amazon.com: TEMCo 88-106 uf/MFD 220-250 VAC Volts Round Start Capacitor...

i have also scoured YouTube but have yet to really find anything. everyone is working on newer units, and the websites and manuals i find are also for newer units. I cannot seem to find anything online about removing the control board.

i did talk to Jim Frerichs. He may be able to help, but i need to remove the control board first.

@kimosabe99, can you tell me if the photos i posted look like yours and if so, how you accessed the control board?


Thanks

As an Amazon Associate Foretravel Owners' Forum earns from qualifying purchases.

Re: Dometic Duo-therm Penguin Issue

Reply #8 –
mm1313
What is the model number of your Dometic Duo-therm units?
Peter    Alberta Canada
'98 U320 40'  Build 5359 M11 450 HP, Aqua hot, Blu Ox

Re: Dometic Duo-therm Penguin Issue

Reply #9 –
I cant really tell if the units were identical.  I worked on mine from the top and was able to remove the board after removing a couple of brackets and some tin work. I'm 1300 miles from coach right now or I'd send some pictures.  Sorry.

jk

Jack and Cathy
1992 U280 Unihome 36' Build #4034
Cummins 8.3 /  Allison MT647/ PacBrake
Apopka, FL / Barre Center, NY

Re: Dometic Duo-therm Penguin Issue

Reply #10 –
Thanks for the replies. I will see if i can access the board from above by removing some of the tin work. didn't seem like an obvious pathway, but i will look again.

Model number is 3106476. Penguin 600 series, and the manuals i have with the coach say they are for "models 600312.321, 600312.421, 600315.321, and 600315.421, used with part No. 3105457".

Thanks

Re: Dometic Duo-therm Penguin Issue

Reply #11 –
I think that the boards for your coach are in a box that is mounted in the air distribution box. That box might come down if you remove some screws.
previous 1984 35 ft ORED 250 HP 3208 Cat       
previous 1998 40 ft U295 CAI 325 hp Cummins
previous 2003 40 Ft u320 build #6140 450 Cummins M11.                                                         
1999 Mazda Miata
Ron, Nancy, Tipper the cat, Max The dog
1997 U 270 36 ft build number 5174 8.3 Cummins

Re: Dometic Duo-therm Penguin Issue

Reply #12 –
In looking at the picture again I am pretty sure if you remove the mounting bolts for the ac you can drop down the large metal framework and remove the box with the board from above it. Someone must have replaced the original ac with a different model than Foretravel used.
previous 1984 35 ft ORED 250 HP 3208 Cat       
previous 1998 40 ft U295 CAI 325 hp Cummins
previous 2003 40 Ft u320 build #6140 450 Cummins M11.                                                         
1999 Mazda Miata
Ron, Nancy, Tipper the cat, Max The dog
1997 U 270 36 ft build number 5174 8.3 Cummins

Re: Dometic Duo-therm Penguin Issue

Reply #13 –
So i managed to get the control board out. For those interested, the control board must come out from underneath. need to remove the metal bracket that holds the unit to the roof, then it drops out. i used a service manual for the Penguin II, which seems to have the same control board as the Penguin (which is what i have). i have 600315.421. ran through circuit board checks in the service manual and it seems to me the circuits in the control board are all working fine. so, this leads me to believe the fan motor must be bad. i ordered a new one. for those interested, i will update once this is replaced.

if anyone has any suggestions or wisdom for replacing the fan motor on a Penguin i would appreciate the assistance. Youtube is helpful, but any tidbits from experience would be nice.

Thank you for the help.

Re: Dometic Duo-therm Penguin Issue

Reply #14 –
Blaster is your friend for the set screws. Take your time and take pictures as you go along.
previous 1984 35 ft ORED 250 HP 3208 Cat       
previous 1998 40 ft U295 CAI 325 hp Cummins
previous 2003 40 Ft u320 build #6140 450 Cummins M11.                                                         
1999 Mazda Miata
Ron, Nancy, Tipper the cat, Max The dog
1997 U 270 36 ft build number 5174 8.3 Cummins

Re: Dometic Duo-therm Penguin Issue

Reply #15 –
If yo can get to the shafts and you need to remove the blower wheels off to get the motor out, cut the shafts off. Get it all down off the roof so you can work on it. As Ron said blaster is your friends and a little heat helps as well.
Bruce, Linda, and Macy
Zoey RIP 1/20/19
1999 U295 40' build #5400
2017 silver Jeep Wrangler, 1260 watts of solar on top
Moving around the country

Re: Dometic Duo-therm Penguin Issue

Reply #16 –
This is the motor I bought and never used from Johnstone Supply you need to measure the shafts on yours before destroying and cut the ones on the new motor to match.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean
 

Re: Dometic Duo-therm Penguin Issue

Reply #17 –
I just wanted to thank everyone for the help and suggestions. the problem was in fact a bad motor. the replacement motor proved to be hard to find, but Dyers RV has the exact match. this includes hardware and everything you need to replace F42C38A61. Easy out, easy replace. took me only a few hours. i did cut the wires from the new one and use the wire nuts that came with the new motor so i wouldn't need to route the wires through the AC metalwork and grommets. Things are working fine now.

Much appreciated.

DYERS RV #82013 - MOTOR REPLACEMENT KIT FOR DOMETIC PENGUIN:
Dometic A/C Penguin Fan Motor Service Kit