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Author Topic: AC not cooling.  (Read 522 times)

Jerry Emert

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AC not cooling.
« on: March 18, 2019, 04:47:25 PM »
AC not cooling so before I replace it I had a couple of questions.
1. What could be causing this.  I know that you cannot generally recharge an RV AC unit.  What do I check first.  It runs and comes on normally just blows warm air.
2. If I have to replace it.  I know it's pretty easy.  4 bolts and a couple of wires.  How do the ducts come into the picture?  Do you have to cut tape or take out screws or something?  Do they just line up and jump into place?  No idea!
As usual, thank you, in advance.
Jerry
Jerry, Chief USN Retired
2003 Patriot Thunder Lexington 40' 3 Slides
C-12 Ser#  2KS89983
4000MH

Bill Lampkin

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Re: AC not cooling.
« Reply #1 on: March 18, 2019, 05:03:53 PM »
Jerry, Lots to consider when replacing A/Cs. (1) If yours are original to your coach, congrats, you got a lot of life out of them. We replaced our 2 Dometic Penguin A/Cs two years ago. Maneuvering a 100+# box up onto the roof takes it out of the do-it yourself category for me. As far as ducting, the ducts are just voids in the roof insulation, so the A/C just sits in place over the duct area, no issue. Use new gasket and tighten screws to proper torque value (not very tight, you don't want to compress the gasket too much. You will have to replace your wall controls (A/C thermostats) with Dometic CCCII units if you want to retain zone control of A/Cs, heat pump and Aqua Hot operation. New Penguin II A/C Heat pumps will require a new control board at each A/C. A very good tech will know this, and will order the correct board from Dometic. If your tech's eyes glaze over when you mention new control board, find another tech! Good luck!
2005 Patriot Thunder Lexington, 3 slides
40' tag axle (short wheelbase)
525 hp C13
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Al Anderson

  • 2002 Beaver Marquis
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Re: AC not cooling.
« Reply #2 on: March 18, 2019, 08:28:43 PM »
I am one of the lucky owners of a Marquis with basement air.  While the primary, basement A/C was replaced by the prior owner, even with a new unit it would only cool at an acceptable level when the outside temperatures were below 85 degrees.  In the desert when the temperatures would climb over 100, the inside would hit 90 degrees.  Hardly sleeping temperatures.
I say all this to say to resolve this I took the advice of others with basement air and decided to supplement the basement air by removing one of my three fantastic fans and installed a rooftop A/C.  The actual installation wasn't too bad except as Bill refers to it, the maneuvering the unit onto the roof.  Even with two of us on the ladder the unit was a battle and awkward at best.  When I did mine, I did a combination of direct vent registers and piping it into the existing duct work.  With the newer 15,000 BTU higher efficiency Dometic Penquin A/C unit, I could get away with running my basement air less and when they are both running, hold 75 degrees regardless of outside temps and sun loads. 
If you feel you are up to tackling getting it on the roof the removal and installation is just time consuming.  You will want one that will integrated with your existing thermostat but the rest is just a process of unbolting/re-bolting, rewiring, cleaning and sealing. I also would consider doing both, or all three if you are so equipped, at the same time.  As these motorhomes age it is only a matter of time till they all need to be replaced.
Al Anderson, 2002 Beaver Marquis, 42 Feet Long
Cat C12 505 HP
2 Slides with a Tag Axle
2013 Wrangler 4 Door
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Jerry Emert

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Re: AC not cooling.
« Reply #3 on: March 18, 2019, 09:09:27 PM »
Thanks to you both.  The front was replaced about 4 years ago and is going strong.  Trying to decide if I am going to do it myself.  Starting to sound like I am going to take advantage of Camping World's "install anything" for 59 dollar deal!  The heat pumps don't make this thing any easier to buy! 
Jerry, Chief USN Retired
2003 Patriot Thunder Lexington 40' 3 Slides
C-12 Ser#  2KS89983
4000MH

Mike Shumack

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Re: AC not cooling.
« Reply #4 on: March 18, 2019, 09:42:29 PM »
If you decide to do it by yourself - call me. I'm available to help on weekends.
- Mike

'05 Beaver Patriot Thunder, Vicksburg, CAT C13  525HP, Allison 4000MH, HydraLift
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Bill Lampkin

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Re: AC not cooling.
« Reply #5 on: March 18, 2019, 10:00:59 PM »
Jerry, No way would I let CW touch my A/C system. Find a reputable shop that knows Dometic multi-zone A/C; with the new units you need a special control board and the new CCCII tstats; won't work any other way and it can confuse even the most experienced techs. When I had mine done, the guys used a forklift and lifted the A/C on its pallet all the way to the roof where two guys then placed it over the vent hole. Check with Dometic to see if they still have the right board for use with your existing 5 button tstat, assuming you are only replacing one A/C at this time. Don't even try to use a control board or tstat unless Dometic says OK. A local shop here burned up our new unit by trying to 'monkey around' using an improper control board. Our two new Penguins work great, but I still need to fix the programming on one of the control board so all the 'zones' work right.
2005 Patriot Thunder Lexington, 3 slides
40' tag axle (short wheelbase)
525 hp C13
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Lee Welbanks

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Re: AC not cooling.
« Reply #6 on: March 19, 2019, 05:07:22 AM »
Jerry, I would not take it to Camping Weird, does you compressor come on when the fan is blowing? Might just be a capacitor needs replaced.
Lee, Judy  & Pepper
06 Beaver Patriot Thunder
Wilmington IV 40
525 Cat, 4K Allison
2013 Honda CRV
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Mike Humble

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Re: AC not cooling.
« Reply #7 on: March 19, 2019, 04:48:20 PM »
Just had mine repaired for a $20 part and 45 min labor.  My clue was there was a burn smell when turned on either AC or heat pump.
Mike
2008 Marquis 45' Cat C-15 600hp
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Jerry Emert

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Re: AC not cooling.
« Reply #8 on: March 19, 2019, 04:52:29 PM »
If you decide to do it by yourself - call me. I'm available to help on weekends.
Thanks Mike.  We're in TN.  Remember if you want me to stop and check on that table in KY I'll be happy to. 
Jerry, Chief USN Retired
2003 Patriot Thunder Lexington 40' 3 Slides
C-12 Ser#  2KS89983
4000MH

Jerry Emert

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Re: AC not cooling.
« Reply #9 on: March 19, 2019, 04:57:24 PM »
Jerry, I would not take it to Camping Weird, does you compressor come on when the fan is blowing? Might just be a capacitor needs replaced.
Thanks Lee, I'll try to tell if the compressor is coming on.  Not sure how.  As usual when traveling I have no clue who is reputable and who isn't to make any kind of repairs.  May let it wait for the Ramblin Pushers Maint. Rally.  We are headed there at the end of April from our boondocking land in TN.
Jerry, Chief USN Retired
2003 Patriot Thunder Lexington 40' 3 Slides
C-12 Ser#  2KS89983
4000MH

Mike Shumack

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Re: AC not cooling.
« Reply #10 on: March 19, 2019, 05:04:49 PM »

Thanks Mike.  We're in TN.  Remember if you want me to stop and check on that table in KY I'll be happy to.

Thanks for offer - but DW says she needs to look at any purchases like that herself to make sure it meets her scuitiny. ;)
On my next trip in that direction, I can stop in and have a look.
- Mike

'05 Beaver Patriot Thunder, Vicksburg, CAT C13  525HP, Allison 4000MH, HydraLift

Jerry Emert

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Re: AC not cooling.
« Reply #11 on: March 19, 2019, 06:29:58 PM »
Jerry, No way would I let CW touch my A/C system. Find a reputable shop that knows Dometic multi-zone A/C; with the new units you need a special control board and the new CCCII tstats; won't work any other way and it can confuse even the most experienced techs. When I had mine done, the guys used a forklift and lifted the A/C on its pallet all the way to the roof where two guys then placed it over the vent hole. Check with Dometic to see if they still have the right board for use with your existing 5 button tstat, assuming you are only replacing one A/C at this time. Don't even try to use a control board or tstat unless Dometic says OK. A local shop here burned up our new unit by trying to 'monkey around' using an improper control board. Our two new Penguins work great, but I still need to fix the programming on one of the control board so all the 'zones' work right.
Bill, does this look like the right board?  I'm very limited in good RV repair places here in Central TN.  Trying to learn as much as I can.  Thanks
https://www.amazon.com/dp/B01B3I9576/ref=sspa_dk_detail_2?psc=1&pd_rd_i=B01B3I9576
Jerry, Chief USN Retired
2003 Patriot Thunder Lexington 40' 3 Slides
C-12 Ser#  2KS89983
4000MH

Bill Lampkin

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Re: AC not cooling.
« Reply #12 on: March 19, 2019, 08:33:52 PM »
Jerry, I would call Dometic to verify which board will work with your replacement A/C and tstat. I thought I had heard that the newer Penguin II A/C heat pumps will not work with the older 5 button tstat, as they discontinued the board that made the 5 button compatible. When I called Dometic the gal there was very helpful and really knew her stuff.  The newer CCCII tstats work great. In my posts, I am assuming that your setup is like mine, 2 ea. A/C heat pumps, Aqua Hot (furnace) and 3 'zones'; living room, bath/dressing, and bedroom. 
2005 Patriot Thunder Lexington, 3 slides
40' tag axle (short wheelbase)
525 hp C13
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Joel Ashley

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Re: AC not cooling.
« Reply #13 on: March 19, 2019, 09:19:05 PM »
As Lee brought up, if the unit fan runs, but no cooling, it could be just a start capacitor;  probably the $20 part Mike had replaced.  There are likely YouTube videos available for guidance about how to determine that and fixes, but cautious discretion should be used in which videos you follow.

Joel
Joel and Lee Rae Ashley
Clackamas, Oregon
36.9 ft. 2006 Monterey Ventura IV, aka"Monty Rae"
C9 400HP Cat
towing a 1997 Ford Explorer Limited, aka "Pearl"
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Jerry Emert

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Re: AC not cooling.
« Reply #14 on: March 20, 2019, 02:48:37 PM »
Jerry, I would call Dometic to verify which board will work with your replacement A/C and tstat. I thought I had heard that the newer Penguin II A/C heat pumps will not work with the older 5 button tstat, as they discontinued the board that made the 5 button compatible. When I called Dometic the gal there was very helpful and really knew her stuff.  The newer CCCII tstats work great. In my posts, I am assuming that your setup is like mine, 2 ea. A/C heat pumps, Aqua Hot (furnace) and 3 'zones'; living room, bath/dressing, and bedroom.
Yes same setup.  I'll call.  Thank you.
Jerry, Chief USN Retired
2003 Patriot Thunder Lexington 40' 3 Slides
C-12 Ser#  2KS89983
4000MH