Question about Dometic Rooftop RV Air Conditioner

2 Answers

I have a duotherm 15000 rooftop rv air conditioner that leaks

Water on the inside after a few minutes.I checked the tray under the coil and seems to be clear.

Posted by on

  • alvinandruth Jun 01, 2010




2 Answers

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points


    An expert that got 20 achievements.


    An expert that got 10 achievements.


    An expert that got 5 achievements.

  • Master
  • 17,970 Answers

On most rooftop air conditioners, you can see the inside (evaporator) coils by looking up through the air return- some models are easier than others, though. This was a Coleman Mach series, so I could just see the coils, but could not access them for a good cleaning, so a trip to the roof was in store.

Getting access to the evaporator coils is not very difficult, you do have to remove the plastic shroud, and then some sheet metal on the front-

I have a duotherm 15000 rooftop rv air conditioner - b9cc9b4.png

Roof Top Air Conditioner- exploded view

This is an exploded view of a DuoTherm BriskAir, but standard Coleman units are pretty much the same. A tip- when removing the screws that hold the sheet metal cover on, pay attention to the screws- there will usually be a few that have a blunt end on them, these are meant to usually go in to the electrical compartments, or where there are wires or tubing. You do not want to find out you put a sharp pointed screw back where it was not used originally.

Once you have the sheet metal cover off, I use a stiff bristle brush to “comb” any large lint off of the fins. Once the “big stuff” is gone, I use a good degreaser- I use VoomRV, because it is PH neutral and a great degreaser, Coleman recommends “Formula 409′. I tend to shy away from most commercial A/C coil cleaners as they are often very harsh on aluminum- they clean the aluminum coils well, but I don’t want the cleaner running down the side of the RV (something you don’t have to worry about in home units).

I soak the coils well, then lay heavy towels over the air intake to catch any water (I put towels inside as well- just in case), then spray the coils off.

This is a good time to check the drain holes for the condensation- there will be holes in the bottom pan on either side of the tray the coils sit in. It’s easy to clean them out. It’s also a good idea to check the gasket-
Air Conditioner gasket measurementmake sure the bottom of the unit is at least 1/2′ above the roof -


It is also a very good idea to check and clean the outside, or condenser coils. Sometimes they will be very clogged- as in the case from Dudes RV Air Conditioner page, but sometimes they might still look clean. Even if they do look clean- clean them any way! In air conditioners that have not been cleaned for a couple of years- and the unit has been used- I will consistently measure a 2 amp drop in current – just from cleaning. You will be amazed at the dirt which will come out of a clean looking coil.

While you are up on the roof with the shroud off, it is also a good time to check the fan motor- some units have oil ports- if yours does, put a few drops of electric motor oil in each port. You can also check the condenser blade. Another unit I serviced ( a DuoTherm) had a fan blade that was starting to go- it was cracking around the shaft attachment, which made it just a little of balance- to the point where it would hit the sheet metal every now and then.

I’ve got to say- RV roof top air conditioners are about the most reliable component on an RV, but they do need regular maintenance. As with most things I talk about, given regular maintenance, they will give years of service. Often RV air conditioners are replaced simply to add new features and lower current draw, not because there is really anything wrong with them.

Hope helps.

Posted on Jun 01, 2010

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points


    An expert that got 10 achievements.


    An expert that got 5 achievements.


    An expert whose answer got voted for 500 times.

  • Master
  • 1,561 Answers


Remove and Place the air unit on a firm surface. Preferably a concrete slab or a few old boards. Do not place the unit on grass or dirt.

Use the screwdriver and remove the outer metal housing of the air conditioner. There are generally 4 to 6 screws along the lower edge of the cover that holds it to the frame.

Observe the inside of the air unit. Note that there is a plastic drain tray on the bottom. This drain tray carries away the condensation water from the cooling coil and allows it to flow to the outdoors and drip to the ground. The drain tray is plugged from last seasons collection of dust and bacteria growth.

Use the cup measure and pour some house bleach into the plastic tray. Allow the bleach to "work" on the nasty solids that have collected there for about 5 to 10 minutes.

Spray in the interior of the air unit with the moderate pressure from the spray nozzle. Force the water into the plastic drain tray and remove all of the solid debris that is laying there. Spray the interior and exterior coils as well since you have the unit cover off. You will have to remove the interior filter as well. Clean the filter while it is exposed.

Place another cup of bleach into the plastic drain tray and allow the liquid cleaner to set for about 5 to 10 minutes than thoroughly rinse the unit with fresh water. The inside area should be thoroughly clean.

Allow the unit to completely dry in the sun. When dry, replace the exterior cover and place the unit back.The unit will be cured of leaking water inside.

Take care.

Posted on Jun 01, 2010


1 Suggested Answer

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

A 6ya expert can help you resolve that issue over the phone in a minute or two.
Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
The service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.
Good luck!

Posted on Jan 02, 2017

Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

DuoTherm mark 2 rooftop ac 620426-321

need to see if drain pan stopped up or fan blowing water off coil

Jul 11, 2013 | Dometic Rooftop RV Air Conditioner

1 Answer

1992 dolphin rv duotherm ac still leaking after cleaning the drain tray holes

Have you checked evaporator fins/coils at front to see if it is those that are frosting up and need cleaning? Also make sure return air and cool air aren't mixing. If some cool air is getting in to return air, from other side, it will cause condensation as well. Some older models did suffer from cracks in drip tray as well. That requires removing cover on top and looking and sealing cracks in plastic drip tray under evaporator and condensor etc. Sometimes it works . Clean well and use good sealant if that's the problem.

Sep 26, 2012 | Dometic Rooftop RV Air Conditioner

1 Answer

A brand new Dometic 15000 btu rooftop unit was driping water into the living space. The condesant tray was clean but the water was not draining out. When I took the inner cover off the cooling coils the...

You will need to contact Dometic directly.
For RV products

Customer Support Center

P.O. Box 490
Elkhart, IN 46515

Phone: 1-800-544-4881

Sales and Marketing
2320 Industrial Parkway
Elkhart, IN 46516
Phone: 574-294-2511
Fax: 574-293-9686

Aug 02, 2011 | Dometic Rooftop RV Air Conditioner

1 Answer

I have a dometic duotherm rooftop air conditioner on a trailer, and when it is running it continues to climb on how many amps it draws. what is the problem?

My caned answer is to clean the coils, turn off the power, and take up a hose and keep the water to just the coil, and clean it good every inch use a stream of water, and hose it out, the indoor coil is not easy to clean but doo able. Good luck

Jul 01, 2011 | Dometic Rooftop RV Air Conditioner

1 Answer

Rooftop RV Air Conditioner: my duotherm rv ac rooftop 15,000 btu the free...

If it's the pencil type, it just pokes into the fins (carefully)
If you look real close with flashlight you should be able to see where it poked in before, usually a couple of inches up from bottom. If it's the little round disc, it snaps in down in bottom corner, there should be a small hole for it in the frame.

May 17, 2010 | Dometic Rooftop RV Air Conditioner

1 Answer

My duotherm 59136.521 freezes up quite often. what are the possible problems &solutions?

Make sure the coils and fans are clean.
Unless there has been a leak in the lines this will solve your problem.

Jun 19, 2009 | Dometic Rooftop RV Air Conditioner

1 Answer

DuoTherm compressor starts but will not continue to run

check condenser fan if running. it will make compressor comes on and off if broken

May 31, 2009 | Dometic Rooftop RV Air Conditioner

Not finding what you are looking for?
Dometic Rooftop RV Air Conditioner Logo

998 people viewed this question

Ask a Question

Usually answered in minutes!

Top Dometic Heating & Cooling Experts

Bill Long

Level 3 Expert

588 Answers

Tim Whalen

Level 3 Expert

3074 Answers

Dan Webster
Dan Webster

Level 3 Expert

8220 Answers

Are you a Dometic Heating and Cooling Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides