RV Air conditioner leaking – reasons and solution

RV Air conditioner leaking – reasons and solution

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Water dripping from the air conditioner inside a RV is a common problem, specially when the ac is continuously running. Whether the water is leaking when its raining or only when the air conditioner is running, both times you need to figure out the root cause before trying to fix anything.

I had faced the leaking issue in my travel trailer couple of years ago and then it turned out to be an issue with my dometic air conditioner drain pan. Many times people get frustrated when the newly installed air conditioner starts leaking water.

Solving such an issue may not be a difficult thing if you can access the air conditioner easily. Water leaking when it rains can cause confusion as to whether its because of leaking roof or due to air conditioner.

Air conditioner in RV often leaks water either due to gasket leakage or because of debris accumulated on drain pan. Solving the water leak issue need you to open up the shroud on the ac and clean the affected area. Lets see the reasons in detail.

1 Drain pan not draining properly

One of the most common causes of the water leaking from air conditioner in RV is drain pan not able to drain the water properly. Which ideally should drain the water from the evaporator coil on the roof instead of inside of the RV.

This can be a result of debris or dirty on evaporator coils or due to blocking of the drain holes due to dirt or due to purposely done sealing. Some people try to fix the water leaking and end up sealing the drain holes which can aggravate the problem. Its important to get to the root cause and fix rather than just trying things like that.

The evaporator coil sits inside the drain pan which collects the water and then pass through small hoes on to the roof. This system may malfunction if the dirt has accumulated on coil or on holes.

The main function of the drain pan is to obviously collect the water from the evaporator coil which is due to the air conditioning process. When you start the air conditioner inside the RV, the evaporator coils start to become cold. The process starts to remove moist air from inside of the RV, and the cold air is pushed inside of the RV. This results in heat transfer and the evaporator starts collecting water which is transferred to drain pan for pushing it out onto the roof.

Cleaning the evaporator coils : If you see that the evaporator coils have dirt on it, clean it with a proper recommended cleaner. Also make sure the small holes are freed from dirt or debris if any.

If you are not comfortable doing the work yourself, do take your RV to a specialist. The air conditioner fixed on top of the roof is held and covered with covers and screws. So you need to be careful and aware of how things are placed there. First step is to remove the evaporator cover which is normally attached using number of screws. Then make use of proper cleaner to remove the debris and dirt.

Steps to clean the drain pan in you RV AC :

  1. Get on to the roof of the RV and locate the shroud. Shroud is a outer cover of the air conditioner unit.
  2. The draining pan will be covered with a different inside cover. Remove the cover using a screwdriver.
  3. You would see evaporator coil as well. Clean the debris and remove any clogs from drain pan and evaporator coil.
  4. Clean the coils and put back the covers safely.

Make sure you carry out this procedures only if you are clear about in and outs about this parts else try to take help from a professional. A wrong foot here could worsen the problem.

2. Leaking due to Gasket being loose or very tight

A rubber gasket is basically used to seal the air conditioner with the roof. It is compressible and hence its upto the technician or RV owner to make it tight or loose. It will normally have 4 or more bolts that fix air conditioner with the roof.

The most important thing with this assembly is to have a gap of at-least half inch between the air conditioner and the gasket. Having said this don’t keep it too loose and neither it should be very tight. This is very critical and if there is no gap left then the water might get trapped and flow inside the RV instead of going on to the roof.

When the air conditioner condensation occurs the water drains at the bottom of AC and the roof. Thus its important to keep some gasket gap for water to escape out on to the roof. Gasket generally is a low maintenance part and can last for many years without issues. But, as anything cannot simply last forever, gasket too will need replacement if its goes bad.

RV Air conditioner leaking

With time it can deteriorate and start to show effects. In which case you need to replace it. A fellow Rver i met at a campground had problems with his Coleman RV air conditioner, the advice that he got from the company was to keep the gasket and drain pan clear of debris using their recommended cleaner. If the air conditioner is under warranty do not touch it yourself but take hep from the company.

3. Drain pipe is clogged

So, we already saw that a drain pan may not be able to handle the water if its filled with debris and dirt. Now, whats the drain pipe functioning? The drain pipe help to take away the water from the drain pan outside on to the rv roof.

The whole process is simple, the evaporator starts getting water due to cooling process which is transferred to drain pan and then drain pipe throws the water out. If the drain pipe is clogged due to debris the water will not be able to flow out. And it will return on to the pan, causing the water leaking inside of the travel trailer or motorhome.

So how do you clear the drain pipe from the blocking? You can either take the motorhome or camper to a specialist technician or can fix the problem yourself by following below steps,

  • First thing that you need to keep in mind no matter what problem you are solving is to turn of the air conditioner before starting.
  • The drain pan may already have some water, and thus make sure you remove/dry it out before starting.
  • Check if there are any debris on the drain pan. Then check for debris at the end of the drain pipe and try cleaning it as far as possible.
  • You can also use a small size soft brush to get the pipe cleaned more thoroughly. Just make sure you don’t overdo it but.
  • Once you are done clearing the debris from the drain pipe and drain pane, use bleach to clear it further. Using bleach will also help in preventing algae growth.


Air conditioner removes moisture as well as dust from the RV. And thus there is great chance of dust causing the clogging inside different system parts that should not be covered with debris. Doing schedule maintenance of the ac unit thus is a good idea so as to keep it running properly. An air conditioner does cost handful of money and thus preventing it for any such issues is a good idea always.

Since the air conditioner resides outside it can take toll due to all the dirt and debris. The cover even though could be strong will take effect due to all the dust and speed. Over the years it may not be as protective as it should be. The shinning sun can cause the plastic to fade in its strength. Thus periodic checking of ac is recommended specially when going on long tours.

G. Yoganand

A RV enthusiast who spends countless hours researching and learning various things related to RV camping. He believes in spending time doing Outdoor activities.
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