Portable Air Conditioner Not Evaporating Water? Here’s What to Do

Do you have a self-evaporating portable AC, but it suddenly stopped evaporating water on its own?

Most newer portable AC models feature an auto-evaporating system that expels moisture out of their exhaust hose. The auto-evaporating system means that you don’t need to manually empty water out of the portable AC.

However, problems can arise when the self-evaporating system stops working or gets clogged up.

In this article, I’ll go over what you should do if your portable AC is not evaporating water. I’ll also explain how a portable AC evaporates water, and how humidity and the dehumidify mode on your portable AC affect auto-evaporation.

What to do if your portable air conditioner is not evaporating water

If you have an auto- or self-evaporating portable AC and it’s not evaporating water, then you will need to check the condensate slinger and the drain system.

Check the condensate slinger

If the condensate slinger is not working your portable AC won’t evaporate water.

The condensate slinger is a fan that is mounted above the condensate drain pan. The slinger fan picks up water and slings it on the condenser to help discharge heat.

portable ac condensate slinger

As the condensate gets thrown on the condenser, the condensate evaporates and gets blown out of the portable AC’s exhaust hose.

Here is a video of a condensate slinger in action (this slinger is on a window AC, but the concept is exactly the same).

Condensate slingers are very effective – they are often able to evaporate most (or all) of the condensation that a portable AC generates when it cools your home.

If the condensate slinger stops spinning, water will build up in the portable AC’s condensate drain pan. Eventually, you’ll need to empty the water out of a portable AC if its condensate slinger goes bad.

So how do you know if your portable AC’s condensate slinger is bad?

One way to check is to open up your portable AC and see if the slinger spins when you turn the portable AC on.

You’ll be able to see water splash around and your portable AC’s condenser coil will get wet.

Some slingers produce a splashing sound when they sling water from the condensate pan – so you can sometimes figure out if the slinger is working by listening to the sounds that your portable AC makes.

If your portable AC’s condensate slinger goes bad, you will need to replace it if you want your portable AC to evaporate water on its own.

Unfortunately, replacing the condensate slinger on a portable AC might be more trouble than its worth for these reasons:

  • Getting a replacement slinger is difficult due to the scarce availability of portable AC replacement parts
  • Some slingers are installed in such a way that makes them difficult to replace. For example, in the portable AC that I own, you need to remove the condenser coil to replace the slinger. 

That’s why you might end up just getting new portable AC if its slinger stops working.

Check for clogs in the condensate drain system

If the condensate drain system in your portable AC is dirty, then water won’t drain down to the slinger.

In a self-evaporating portable AC, the condensate drains from the evaporator coil down to the condensate drain pan where the slinger is located.

If the drain system from the evaporator coil to the drain pan is dirty and clogged, water won’t evaporate out of your portable AC. Instead, water will build up around the evaporator coil and eventually leak out of the AC.

That’s why some portable ACs have two drains – one drain for the evaporator coil near the top, and another drain for the main condensate drain pan on the bottom of the unit.

If your condensate drain system is clogged, the float switch will activate and your portable AC will shut down.

You’ll need to open up your portable AC and remove all the clogs from the condensate drain system. Clean out all the muck and grime from the condensate drain pans and holes to get your portable AC draining properly again.

Check the humidity in your home

If the humidity in your home is high, then your portable AC won’t be able to evaporate water on its own.

High-humidity environments will cause a portable AC to generate excessive amounts of condensation. So if you use your portable AC on a really humid day, you’ll need to drain it out every so often so it doesn’t overflow with water.

If the humidity in your home is at a moderate level, the AC should be able to expel all the moisture on its own – so you won’t need to drain it often, if ever.

How a portable AC evaporates water

A portable AC evaporates water by using a condensate slinger to sling condensate on the condenser coil.

When the condensate comes into contact with the hot condenser coil it evaporates and gets blown out of the exhaust hose.

The condensate slinger also helps the portable AC run more efficiently by cooling the condenser coil off with water.

Not all portable ACs evaporate water automatically. Only the newer auto- or self-evaporating portable AC models with slingers will evaporate water automatically. Older portable AC models without slingers need to be drained out manually.

Using a self-evaporating portable AC in dehumidify mode

If you use your portable AC in dry or dehumidify mode, then it won’t evaporate water on its own.

A portable AC doesn’t self-evaporate in dehumidify mode because it needs the hot condenser coil to reheat the dehumidified air.

If your portable AC self-evaporated in dehumidify mode, the moisture would end up back in your home instead of in the condensate tank.

Hi, my name is Trey Lewis and I’m the founder and chief editor at HVAC Training Shop. My goal for this website is to help homeowners troubleshoot and maintain their home’s HVAC systems. Whether it’s changing an air filter, troubleshooting a blower motor, or just buying a new humidifier, I want to make sure that you’re covered.

2 thoughts on “Portable Air Conditioner Not Evaporating Water? Here’s What to Do”

  1. This article was very helpful. I bought 2 identical portable AC units on holidays in Spain. One worked perfectly and the other kept having to be drained. The symptoms are an exact match to the ones in the article.

  2. Hi, I am confused. I have 2 identical Danby portable ac’s 8000 btu’s each. I use one for the bedroom and 1 in the living room. Both have 2 drains so I assume they are self evaporating. however, it gets very humid here in the summer and each of them overflowed from the bottom drains so I attached drain hoses to both at the bottom. that solved the problem but you state the hose should only be attached to the top drain ? neither of them stopped on their own when the bottom drains were full causing leaks. Now, one of my exhaust hoses was chewed out by birds and I want to discard it and use the ac in dry mode only, no exhaust hose. Where should I attach the drain hose ? I am worried if I attach to upper drain, I will get a leak at the bottom like I did a while back. I assume your logic is if the drain hose is attached to the top drain, water won’t have a chance to pool at the bottom ?


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