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Author Topic: Heat Pump Dripping  (Read 829 times)

Jerry Emert

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Heat Pump Dripping
« on: October 09, 2019, 01:28:43 PM »
The heat pump has been dripping water inside over the last few nights.  Pulled the cover off the AC yesterday to check for junk in the pan and no clogs up there.  I do not think I have drains on the AC units.  They drain off the roof.  Replaced the rear AC a few months ago and couldn't find any drain lines there.  In the low 50s outside at night.  Ideas?  Thanks
Jerry, Chief USN Retired
2003 Patriot Thunder Lexington 40' 3 Slides
C-12 Ser#  2KS89983
4000MH

Mike Shumack

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Re: Heat Pump Dripping
« Reply #1 on: October 09, 2019, 02:36:39 PM »
What is the humidity like in the coach?

Googling your problem - you're not alone. There are plenty of posts on this subject.
This is a common description of the heat pump operation:

 
Quote
There are two sets of coils in a heat pump, one is inside and one is outside. When in air conditioner mode, the heat pump pumps heat from inside to outside: the inside coil is cold (and has condensation on it) and the outside coil is hot. Many air conditioners provide a drain tube from this coil so no water drips inside the coach (mine just always drains onto the roof and drips all summer.)

When in heat mode, the cycle is reversed and it pumps heat from outside to inside. The outside coil gets cold and the inside coil gets hot. Now, any condensation is happening on the outside coil. This is a different drain pan than the one that collects the condensation when air conditioning. Either that pan doesn't have a drain tube, or it is plugged and the pan is overflowing.

That coil has outside air blowing over it and there is no filter. So dust and dirt can accumulate on it and then that dirt can be washed down by the condensate. So it doesn't take too much of a stretch of the imagination to say that a drain tube (if there is one) could get clogged.

So if you don't have a roof drain (and the drain opening from AC unit onto the roof is not clogged), the solution seems to be, to raise one end of the coach so the water runs off in a different direction.
Good luck
« Last Edit: October 09, 2019, 04:13:49 PM by Mike Shumack »
- Mike

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

Jerry Emert

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Re: Heat Pump Dripping
« Reply #2 on: October 17, 2019, 05:03:22 PM »
The solution can't be to jack up one side of the coach.  We are completely level which should be the goal.  The humidity inside the coach is 37% which is not high.  Temp down to 37 last night and heat pumps continued pumping out heat.  Today the heat pump is dripping again.  I'm sure I only have a rudimentary understanding of the heat pump operation.  When cooling, the water condenses on the outside coils and, in my case seems to, drain out of the pan and off the coach.  When heating that operation is basically reversed and condensation is on inside coils.  So where is that water supposed to go.  Is my understanding correct?
Jerry, Chief USN Retired
2003 Patriot Thunder Lexington 40' 3 Slides
C-12 Ser#  2KS89983
4000MH

Mike Shumack

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Re: Heat Pump Dripping
« Reply #3 on: October 17, 2019, 05:59:15 PM »
I've read that there are two different drain paths/holes (or flows) for the AC unit, one is when in AC mode and the other is for the Heat Pump. So you need to go up top pull the cover and see if the drain hole for the heat pump is clogged.

However, I have not seen or read anything in the Dometic manual that supports this "separate-two drain hole" theory.
There is this ...



 
- Mike

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

Jerry Emert

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Re: Heat Pump Dripping
« Reply #4 on: October 17, 2019, 07:51:23 PM »
I took off the covers for both ACs last week.  There were no blockages.  The only other I can think of is the inside one is freezing and dripping.  Hoping someone has had the same issue and can shine some light on it.  Thanks
Jerry, Chief USN Retired
2003 Patriot Thunder Lexington 40' 3 Slides
C-12 Ser#  2KS89983
4000MH

Steve Huber Co-Admin

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Re: Heat Pump Dripping
« Reply #5 on: October 18, 2019, 12:04:47 AM »
Jerry,
You could try running the fan(s) on High rather than on Auto. This stops freeze ups and dripping water in the AC mode so should also have a similar effect in the heat mode.
Steve
Steve
2015-          07 Contessa Bayshore C9,  400 hp
2013-2015: 00 Marquis Tourmaline, C12, 425 hp
2005-2013: 01 Contessa Naples, 3126B, 330 hp
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Jerry Emert

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Re: Heat Pump Dripping
« Reply #6 on: October 18, 2019, 12:44:39 AM »
Will try this Steve!  Thank you.
Jerry, Chief USN Retired
2003 Patriot Thunder Lexington 40' 3 Slides
C-12 Ser#  2KS89983
4000MH

Jerry Emert

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Re: Heat Pump Dripping
« Reply #7 on: January 22, 2020, 02:58:26 AM »
Had to stay in the coach at an RV tech's place in Brooksville a few nights a few weeks ago.  It got into the 30's so I had the heat pumps on with fans on high.  Took a few hours but they started dripping into the coach again.  I've had the top covers off and the secondary insulated cover inside the outside cover off of on the front unit.  There are no obstructions in the drain pans or drain holes.  The AC units have been on cool frequently lately and they drain off the roof like normal.  Any more ideas?
Jerry, Chief USN Retired
2003 Patriot Thunder Lexington 40' 3 Slides
C-12 Ser#  2KS89983
4000MH

Bill Sprague

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Re: Heat Pump Dripping
« Reply #8 on: January 22, 2020, 04:58:36 PM »
Use the AquaHot for heat?   

Our primary source of heat turned out to be a oil filled, horizontal baseboard style space heater.  It was silent!  If it got too cold, the HydroHot came on.  Using the heat pumps was irritating because of the drafts and noise.
Bill Sprague
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Past 12 year owner of '04 Monterey w/Cummins ISC 350

Mike Shumack

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Re: Heat Pump Dripping
« Reply #9 on: January 22, 2020, 08:30:04 PM »
Had to stay in the coach at an RV tech's place in Brooksville a few nights a few weeks ago.  It got into the 30's so I had the heat pumps on with fans on high.  Took a few hours but they started dripping into the coach again.  I've had the top covers off and the secondary insulated cover inside the outside cover off of on the front unit.  There are no obstructions in the drain pans or drain holes.  The AC units have been on cool frequently lately and they drain off the roof like normal.  Any more ideas?

Is the water dripping out of the air discharge opening, or is it condensing on the ceiling near/around the opening?

If it is dripping out of the air discharge perhaps the metal surround is not insulated well enough allowing the warm discharge air to contact cold metal as it blows out of the opening.
- Mike

'05 Beaver Patriot Thunder 525, Vicksburg, CAT C13, Allison 4000MH, HydraLift
Orlando, FL
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Jerry Emert

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Re: Heat Pump Dripping
« Reply #10 on: January 22, 2020, 08:57:04 PM »
Good thoughts.  I'll check when I can.
Jerry, Chief USN Retired
2003 Patriot Thunder Lexington 40' 3 Slides
C-12 Ser#  2KS89983
4000MH