Author Topic: Replacement roof AC  (Read 7443 times)

Joe DeWeese

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Replacement roof AC
« on: February 17, 2022, 05:21:50 PM »
I own an ‘06 Monterey Laguna iV.  My front roof AC is slowly dying.  I’m looking for a replacement.  Based on the info label inside it is a Dometic Duo-Therm 630516.  However, it appears that model is no longer made.  I contacted Dometic looking for a replacement part number.  The customer support rep. sent me a Model #651816.  However this appears to be a heat pump/air conditioner.  The customer support said that this is the replacement model.  I don’t need or want a heat pump, just an AC.  Is here another AC part that would be a direct replacement for my current model?
Thanks, Joe D.

Bill Lampkin

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Re: Replacement roof AC
« Reply #1 on: February 17, 2022, 05:37:29 PM »
Joe, the heat pump is just an A/C running in reverse; other than one valve, there is no difference betwixt the two units. Go with the heat pump unit, you do not have to use the heat pump feature, it will work as AC only just fine.
2005 Patriot Thunder Lexington, 3 slides
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Bryan Beamon

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Re: Replacement roof AC
« Reply #2 on: February 17, 2022, 11:23:17 PM »
Joe, you probably know this but as a reminder you will need to order an adapter for your thermostat if you have the 5 button thermostat for it to function with your new AC.
C & Bryan Beamon
2006  to present
2007 Contessa 42ft Cat C-9 400hp
1996 to 2006 97 Beaver Patriot Camden

Joe DeWeese

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Re: Replacement roof AC
« Reply #3 on: February 17, 2022, 11:48:57 PM »
Hi Bryan,
     No I did’t know that.  I assumed that since I was told by a Dometic customer support rep that this new Dometic (Model 651816) is a direct replacement for my current one (Model 630516) replacement would only require the AC unit and a new gasket. 
     Thanks for the heads up.
Joe D

Joel Ashley

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Re: Replacement roof AC
« Reply #4 on: February 17, 2022, 11:54:04 PM »
We have the original Duo-therm roof units too and one’s AC is gone.  If lucky, all it may need is a start capacitor, so think about having a trustworthy tech check that possibility before spending on a whole new unit;  there are YouTube videos that describe checking it yourself.   And, yes, a model change requires a thermostat adapter.  There’s been much angst expressed in forums about that and incorrect or negligent tech work regarding it.  It’s one place, since absorbing Duo-Therm, that Dometic hasn’t necessarily helped replacements be easy.

Unfortunately, the units’ shells are now so brittle that they crumble during removal to access the roof parts.  Replacement shells are ~$136 but are touted to be of better materials than were used in 2006. 

Regarding the heat pump aspect, ours both have that feature and we’ve found them useful.  When watching TV in either the bedroom or the living area, the hydronics system’s heat exchangers are annoyingly loud.  By running roof heat in the opposite end of the rig instead, and aiming the roof ports appropriately, interfering heating noise is effectively limited.  Of course the limitation is that heat pumps don’t work in outside ambient temps much below 40F.  I’d rather have the option than not, and the thermostat should already be set up for it if techs are well versed in the update parameters.

Joel
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Reese Hunt

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Re: Replacement roof AC
« Reply #5 on: July 15, 2022, 02:59:56 PM »
I am a little late as usual, yet this info may be useful.

I replaced both roof top Dometic 13k original units with RV AC 15K Houghton, Bellaire 3600 heat pumps.
They are very quiet, variable speed and require only 120vac connections. The controls are remote or on the unit.
Mine were for ducted installation and required a little duct board fabrication. They fit the standard 14x14 hole.
Our coach is 40’ and sitting in 100+ degree, direct Sun, is staying very cool.
These units are made in Australia and sold by Rec-Pro.
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Fred Cook

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Re: Replacement roof AC
« Reply #6 on: July 15, 2022, 11:54:17 PM »
Replaced my front AC last month with a Dometic Penguin II 13.K, Model 640315CXX1C0. Dometic said it was a direct replacement for my 2002 unit. Was able to plug directly into the controller and did not need to change out the thermostat which also controls the Aqua hot furnace settings. Believe you should be able to accomplish the same.
Fred & Cindy
2002 Beaver Patriot Thunder 455, C12 CAT
Towing 2019 Chevy Equinox, AWD Diesel
South Central Missouri, US Army Retired
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Bob Stone

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Re: Replacement roof AC
« Reply #7 on: July 17, 2022, 10:20:53 AM »
I have two Dometic Penguin 2 DuoTherm A/C's on my 2005 Monterey. The front unit is a 15,000 BTU combination air conditioner/heat pump. On a recent trip the A/C started blowing “hot” instead of “cold”. This is a symptom of a failed Reversing Valve. The default is for the unit to go to Heat mode.


The local RV Dealer just wanted to replace the unit without even looking at it. I ordered a new solenoid  coil for the reversing valve on Amazon (they were in short supply for a while). I installed the new coil yesterday and the unit is now blowing cold but the rear unit fails to even turn on. Hopefully just requires a “Reset” on the thermostat. A $200 part instead of a $2,000 new A/C plus 2 new thermostats plus labour.


Update: Yep, a simple thermostat 'reset' got both A/C working as they should.
« Last Edit: July 20, 2022, 01:47:22 PM by Bob Stone »
Bob Stone
'05 Monterey Laguna IV  Cat C-9
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Al Postma

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Re: Replacement roof AC
« Reply #8 on: July 21, 2022, 05:21:34 AM »
Bob,
How do you reset the thermostat?
2007 Beaver Contessa 42ft
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Bob Stone

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Re: Replacement roof AC
« Reply #9 on: July 21, 2022, 05:40:59 AM »

SYSTEM RESET


a. Turn the ON/OFF switch to “OFF” position.


b. Simultaneously depress and hold the MODE and ZONE push-buttons while turning the ON/OFF switch to “ON”. FF should appear in the LCD display until the MODE and ZONE push-buttons are released.


c. When a dip switch is turned on or off after initial configuration, a system reset will need to be done before the Comfort Control Center TM will recognize the updated selection.
Bob Stone
'05 Monterey Laguna IV  Cat C-9
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Al Postma

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Re: Replacement roof AC
« Reply #10 on: July 22, 2022, 10:33:04 AM »
Thank you Bob, I appreciate that.
2007 Beaver Contessa 42ft
Cummins 400hp
08 Hummer H-3 Alpha