Portable Air Conditioner Blows Cold Then Warm- Why?

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Portable air conditioners are very useful yet confusing in their actions sometimes. We all know electronic devices can be so complicated. Such as a portable air conditioner. It often blows more cold than warm air. 

So, why does your portable air conditioner blows cold then warm?

Reasons behind portable air conditioners blowing cold then warm air can be several. A minimal power charge, humidity in the unit, and blocked evaporator fins. A faulty expansion valve or overcharging can cause to blow cold and then warm. There are specific ways to figure out and fix the problems.

How far does the overview seem helpful to you? Cause we have more to show you regarding this. Wanna have a look at it? Great! Dive into our following segments-

Portable Air Conditioner Blows Cold Then Warm: Problems and Solutions!

Portable air conditioners can be used for so many purposes. And people are really advising to buy one in summers.

You can use it in vehicles, vans, or mobile houses as well. You can even duct a flex in the mobile house to shift a portable AC. 

Now, what exactly does it mean if your portable air conditioner blows cold than hot air? There are a number of causes responsible for this. This problem can also be solved by employing plenty of approaches.

portable air conditioner blows cold than hot air
Source: timesofindia

So let’s have a look over them one by one.

Problem 1: Extremely Low or High Percentage of Charge

A lower percentage of power charge might cause the heat exchanger to become cold. That results in the moisture on the evaporator blades freezing. 

The ice accumulates to the point that it obstructs ventilation. The AC system then turns off the compressor, resulting in the warm, humid air.

You’d assume the reverse would be true. That such a lower charge might lead it not to become extremely cold. To understand why this is flawed, you must first learn how refrigeration works.

The evaporator will maintain slightly above freezing temperature with the right refrigerant charge. And it will generate air at approximately 40°F. Generally, it doesn’t take long to cool down an apartment with air conditioners. But portable air conditioners are different. 

After converting states to vapor, this should absorb a maximum of 10°F additional heat. It should do this before exiting the evaporator. Also, before flowing into the compressors or accumulator to finish the cycle.

When a system’s charge is low, the vapor coolant remains in the evaporator longer. It starts removing much more heat from the chamber air flowing over the coil. The refrigerant exiting the evaporator is more than 10°F superheated. 

The heat taken from cabin air leads the air conditioner temperature to drop below freezing. The evaporator freezes due to the moisture in the cabin air. 

Moisture accumulates to the point that ice restricts the airflow over the evaporator. This turns off the air conditioner and prevents it from cooling.

Also, an overcharged portable air conditioner system may first blow chilly air. However, the cold air quickly becomes heated. Since the high side pressures grow to the point. It’s where the high-pressure valve turns off the compressor clutch. 

Once the pressures have balanced, the high-stress switch enables the compressor to restart. The cycle is repeated indefinitely. Delivering a short spell of cold air followed by a period of warm air.

Solution: Evacuate and replenish the portable air conditioning system. For that, you would need a vacuum gauge. For a good micron gauge, you can choose the Digital Manifold Gauge Set. You can find it on amazon.

Problem 2: Clogged Cabin of Air Conditioner Filter

A clogged cabin air filter may potentially cause the evaporator to freeze.

Low airflow is caused by a blocked cabin air filter, like a low refrigerant charge. It leads the refrigerant to extract too much heat. Also, it causes the evaporator to freeze.

The cabin air filter captures all of the detritus in the fresh air. Such as leaves, dust, and pollen.

Solution: If you are facing this issue, then it’s best to replace the air filter. In that case, finding air filters for portable ACs are very rare. Yet, we have the NLR Air Filter in our mind. You can find it on amazon.

Problem 3: An Electrical Error In the System

The A/C system in portable air conditioner is a maze of cables, controls, and fuses. Under normal working conditions, these components work together to provide electricity to the A/C. It allows you to have cool air on demand.

If these components fail, your air conditioner may get shut down. Then it might begin spewing heated air. While this helps to avoid a deadly fire hazard. Also, a single-blown fuse might force your entire air conditioning system to go down.

Solution: Try to check the system carefully. Maybe a blown fuse or a damaged one causing the trouble there. Change the fuse or replace the circuit, if it needs to. 

Problem 4: Leak Inside of Portable Air Conditioner System

One of the most typical causes of leakage inside a portable air conditioner is refrigerant leak. 

Refrigerant leak is often produced by a combination of moisture and refrigerant. Which when combined produces a destructive acid. That eats away at the portable air conditioner system seals, valves, and hoses. 

As there is not enough coolant in the existing system to chill things down. Leakage in your portable A/C can cause this to spew cold and then warm air.

In a worst-case scenario, the acid can damage the interior of your compressor. It can cause metal shards to migrate throughout the air conditioner system. Also, it can cause severe obstructions, damages, and component failures.

Solution: Try to find out the leakage. And cover up the leakage inside the portable air conditioner. Professional grade superglue can be used. You can find it on amazon.

Problem 5: A Broken Compressed Air Clutch

One critical component of a portable air conditioning is the air conditioner compressor clutch. It enables the pulley to activate and disconnect from engine power. It allows the compressor to operate only when necessary. 

Because it constantly cycles in and out, it is prone to wear. And also tear every time whenever you run your air conditioner.

When the compressor clutch fails, your air conditioner will not blast cool air for long. A compressor that is broken cannot adequately compress the coolant in the portable A/C. The system also can’t blow the cool air that you need.

Solution: The only solution for this problem is to replace the broken compressed air clutch. Since it is already broken and damaged. 

A good quality compressed air clutch will be required for the system. In that case, you can look at AC Compressor Clutch Replacement. You can find it on amazon.

Frequently Asked Questions (FAQs)

What is the maximum level of heat that your portable air conditioner can tolerate?

The temperature for a portable air conditioner should be 10℃ lower than the outdoor temperature to tolerate .Sometimes it gets too hot outdoors. In situations like this, a portable air conditioner won’t be able to reach low temperatures. The ambient temperature must be adjusted. 

Could a portable air conditioner keep a room cool if the doors are left open?

No, portable ac can’t keep a room cool if doors are open. Your portable air conditioner will not be able to chill your room. When the windows and doors are left open. Open windows and doors give a direct conduit for hot air from outside to enter your conditioned area.

How should a portable air conditioner be used in a room?

Shut the doors and windows first to use a portable ac in a room. Portable air conditioners are most effective in small spaces. If you’re being used in a bedroom and basement, lock the house. So that additional heated air isn’t introduced and cold air can flow.


We hope now it’s clear why your portable air conditioner blows cold than warm air. 

Also, you will be able to fix the problems on your own now. Still, something you need to learn, drop the questions here. We would love to help you out!

All the best with your portable air conditioner fixing!

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