Why do some portable air conditioners have two drains?

Some portable air conditioners have two drains equipped for draining manually in varying humidity levels and it is important to monitor the level of water that accumulates internally.

Portable air conditioning units differ from other types of air conditioners on the market for a number of reasons. Firstly, they are portable so you can move them around, and they also need to drain condensate water accumulated from cooling or dehumidification.

Some portable units have a drain for manual draining whereas others have two drains. If your portable air conditioner has two drains, you might be wondering why and how to drain each one.

Portable units with two drains

A portable AC can be convenient for people who want efficient cooling no matter where they are in their home or space.

These units also require close monitoring when it comes to the amount of water collected inside from condensation that needs to be drained for it to continue working efficiently.

The draining process is important in the cycling and operation of a portable unit and needs to be done manually. Some portable units have two drains, so it is important to know the purpose of each one.

Why do some portable air conditioners have two drains?

If you own a portable air conditioner with two drains, you need to know the function of each one to ensure you drain them accordingly.

Some portable air conditioner owners may notice these two drainage plugs on their units and because the unit should have a self or auto evaporation mode, they may neglect to perform drainage.

This should be avoided as drainage is necessary even with units that have auto evaporation modes. This is important when humidity is at its highest and the unit accumulates more moisture than is expected.

Portable units with two drains have an upper drain and a lower drain. The upper drain is intended for automatic draining when the reservoir is full, and the lower drain is used to drain the tank for storage.

The upper drain is the continuous drain outlet that accumulates water specifically when the unit is in dehumidification mode.

The lower drain accumulates water in cooling or heating mode. You need to check the user manual of your portable air conditioner for the steps you need to follow to safely drain each of the drain plugs to avoid causing damage.

Depending on the model you have, the unit will warn you when excess water is accumulated either by flashing warning lights or by shutting off suddenly.

How to drain your air conditioner

To drain your portable AC, you either need a drain pan, a drain hose or a condensate pump, all of which you can shop for on Amazon. To use the hose you need to rely on gravity by placing it flat on the ground when you have firmly secured the hose.

For a pan, place the pan under the drainage hub and unplug the drain plug so that the water can drain completely before reattaching the drain plug. A condensate pump pumps the water out of the drain by pushing it out.

Drainage tools Description Amazon price

Forestchill Drain Hose

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·    60 cm drain hose

·    High quality hose made of weather-proof PVC

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·    Universal fit for 5/8 inch and 3/5-inch drain hose adaptors


Little Giant Condensate pump

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·    Automatic condensate pump

·    Thermally protected motor

·    Built-to-last stainless steel motor shaft and CSA certified to US standards

·    Includes safety switch and 20 feet vinyl tubing


Diversitech Drain Pan

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·    Large HVAC drain pan

·    Made of non-toxic materials

·    Prevents spills with a depth of 2 inches of water


What happens if you do not drain your portable air conditioner?

Fortunately, newer portable air conditioner models have an automatic shut-off sensor that switches the unit off when the condensate water has accumulated to a certain level and needs to be drained.

Your unit, therefore, cannot cool if you fail to drain it. If your unit does not have a shut-off sensor, the water will spill over and damage the unit and its internal components extensively, and your home will become a bacterial breeding ground.

How often does the unit need draining?

How often you drain your portable unit depends on the climate you live in. Essentially, the level of humidity determines how often you need to drain your air conditioner.

If the humidity levels in the air are high, your unit will accumulate water at a more rapid rate. Typically, standard portable units have storage tanks that need to be drained every eight hours but this, again, depends on the levels of humidity in the air.

1 thought on “Why do some portable air conditioners have two drains?”

  1. I have a chilly 9000 but with two drainage points.i have drained the bottom one. But not sure if I should drain one hLf way up machine.. worried this might be place you put in new coolant . No explanation in manual . So haven’t done it yet. Ac unit not sending temp down


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