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Topic: Problem w/ Dometic Penguin 15k BTU w/ Heat Pump (Read 1104 times) previous topic - next topic

Problem w/ Dometic Penguin 15k BTU w/ Heat Pump

When running in cooling mode on warmer days, the rear unit appears to switch into heat pump mode, blowing hot air.  Turn off and restart later it cools for a while and then into heat pump mode again.  Year before last, it did this on hot days a couple of times.  Last year also a couple of times.  Now although days are not "hot" yet, low 80's, it happens daily.  Unit is 14 / 15 yrs old. Has anyone experienced this problem?  If so, how did you remedy?  Thanks for your replies.
Bill and Joyce, The House2 and Dashboard Pig III
2000 U320 4210 CAI (The House2)
Build # 5733
2019 F150 King Ranch FX4

Re: Problem w/ Dometic Penguin 15k BTU w/ Heat Pump

Reply #1 –
Bill,

It sounds like the solenoid that does the switching between A/C and heat is getting either hot or weak and cycling off. IIRC on those units the swap valve defaults to heat if you have a coil failure. The coil can be replace with ease and is available off the net or a local A/C supply store.

Mike
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: Problem w/ Dometic Penguin 15k BTU w/ Heat Pump

Reply #3 –
Thanks Mike & Jim for your help. I'll replace the solenoid and let you know if that fixes. 
Bill and Joyce, The House2 and Dashboard Pig III
2000 U320 4210 CAI (The House2)
Build # 5733
2019 F150 King Ranch FX4

Re: Problem w/ Dometic Penguin 15k BTU w/ Heat Pump

Reply #4 –
BTW, our experience is that only roof AC units cool and several other device can cool, so it may be better to not add complexity to a roof unit when we will not use it for heating.  So we do not have heat pumps, just compressor coolers.  Also heat from above does not reach the floor as well as a floor space heater.

Re: Problem w/ Dometic Penguin 15k BTU w/ Heat Pump

Reply #5 –
Quote from: Barry & Cindy –
  our experience is that only roof AC units cool and several other device can cool, so it may be better to not add complexity to a roof unit when we will not use it for heating. 

I don't agree. We've had heat strips in both our previous coaches and used them a lot up north to "take the chill off". They actually do a good job before the big furnace gets up to speed. Down here, not worth the extra expense. We don't have heat strips on the current Carriers, but, hey, it's a "Texas Coach"!
1993 U-240 "La Villa Grande"..CAT 3116 w/ Pacbrake PRXB...Allison 3060 6-speed..
Previous: 1983 Airstream 310 turbo diesel, 1979 Airstream 280 turbo diesel
                                      Build # 4297
                                      PNW natives
                      Home base:  'Cactus Hug' (Ajo, Arizona)
                        DW Judy & Chet the wonder dog
                        Full-Timers 'Sailing the asphalt sea'

Re: Problem w/ Dometic Penguin 15k BTU w/ Heat Pump

Reply #6 –
Are the heat strips controlled by the thermostat?
Forest & Cindy Olivier
1987 log cabin
2011 Roadtrek C210P
no longer 1999 36' U320 build #5522
2013 Rzr 570 & 2018 Ranger XP1000
2006 Lexus GX470
2011 Tahoe LT 4x4
Previous 1998 45' 2 slide Newell, 1993 39' Newell

Re: Problem w/ Dometic Penguin 15k BTU w/ Heat Pump

Reply #7 –
If the solenoid does not fix the issue Bill you can try unplugging the phone cable connectors that attatch the gray cable to the black cables coming down from the ac. Sometimes they get some corrosion and then the thermostat gets confused. At least that is what I found was happening on our front ac.
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: Problem w/ Dometic Penguin 15k BTU w/ Heat Pump

Reply #8 –
Interesting about heat strips.  We just removed our heat strips to give us better access to cleaning the evaporator surface from inside the coach.  They came out real easy.

Over 17 years we never turned heat strips on, partly from louder sound than a small space heater, and heat on head instead of heat on feet.

But the real reason is we figured that 'saving' the roof unit for cooling would extend their life.  And since we only had heat strips the 'wear' would just be the blower motor.  The addition of heat-pump's high-pressure switching valve and louder compressor running to heat an RV feels less efficient than other choices.

I could see the convenience of heat pumps especially since they turn on and off from central thermostat.  Also some do not like floor plug in space heaters.  And since so many Foretravels have heat pumps, assume they are used for heat a lot.

We are not in very cold weather, so our propane furnace run is short on a cold morning.  Also we are often plugged into shore power, so it makes sense for us to run small space heaters over extended hours.

When we change our roof air conditioners, we would not choose a heat pump model, even if less expensive.  Air conditioners and refrigerators often have long lives because the refrigerant is completely sealed.  Adding a movable valve to a sealed system can be a new weak point.

Re: Problem w/ Dometic Penguin 15k BTU w/ Heat Pump

Reply #9 –
I removed the roof ac cover and located the reversing valve. Removed and replaced the coil to inspect and inspected all connections. Unit has worked fine since. I have ordered a new coil to have on hand. Thanks Mike and Jim for you advice and link for coil. And thanks Ron, I did not check that connection but will do so. 
Bill and Joyce, The House2 and Dashboard Pig III
2000 U320 4210 CAI (The House2)
Build # 5733
2019 F150 King Ranch FX4