Why Does A Air Conditioner Ice Up And How To Fix It?

Why Does A Air Conditioner Ice Up And How To Fix It

In this blog post, I will go over the various reasons an air conditioner will ice up. I will also go over the various things to look for and how to fix them.

Get your Air Conditioner to STOP ICING up and back to working correctly.

If your home air conditioner system is icing up there are several reasons why this is happening. A residential split system can ice up at the inside evaporator coil and it can also ice up at the condenser.

At the outside condenser, the copper line-set will get ice on it and so can the compressor motor at the bottom of the condenser. Occasionally the condenser coils will also start to get ice on them.

Dirty Air Filter

Why Does A Air Conditioner Ice Up And How To Fix It
Clean and dirty home air filter

The filter for the system is extremely dirty and restricts airflow. Check your system’s air filter. Some systems have more than one filter. If the filter is dirty simply, replacing the filter may be the solution.

Change the filter and then go to your thermostat. Turn the fan to the on position. It is most likely in the auto position.

Then turn the cooling setting on the thermostat to the off position. This will allow the blower motor to run without the outside condenser turning on. This will allow the ice to melt on the inside evaporator coil and give the ice on the outside condenser time to melt. After some time has passed and the ice has melted turn the cooling setting on and the fan back to the auto position. Allow the system to run and if no ice reappears and the system works then the problem is solved.

Dirty Evaporator Coil

Why Does A Air Conditioner Ice Up And How To Fix It
Dirty evaporator coil

The evaporator coil is on the system inside the home. Regardless if you have a gas furnace or electric air handler on the inside you have an evaporator coil. An evaporator coil can become dirty when dust and various other debris in the air make it past the home filter. The evaporator coil has a cover that can easily be removed or even just cracked open to see if the coil is dirty. Some systems even have an access door you can open to view the evaporator coil. If the coil is extremely dirty and impacted it will need to be cleaned. A dirty coil will cause the system to ice up. Use an approved evaporator coil cleaner to totally clean the coils. Make sure to not use anything to bend the coil fins. A common mistake I see people make is using a brush of some sort and doing more damage than good. Let the low-pressure water and cleaner do the work. After the coil and filter are totally clean turn the system on and make sure it doesn’t ice back up.

Blower Motor Bad

reasons why the air conditioner breaker will trip

If the blower motor is damaged and not turning as fast as it should the evaporator coil temperature will drop below 32 degrees and start to freeze up. The freezing can extend from the inside coil all the way out to the outside condenser.

The inside blower motor not blowing at all or spinning much slower than normal you may need to change out the blower motor. If your blower motor has a capacitor you will need to test that with a multimeter. If the capacitor is very weak then change that before changing the blower motor. In some cases, it will be obvious the blower motor is bad. In that case, the blower motor and capacitor will need to be replaced.

Low On Refrigerant

DON’T JUST ASSUME THE REFRIGERANT IS LOW AND THAT’S THE PROBLEM. Check other parts of the system first. **NOTE** If the system condenser and the evaporator coil are not clean you will not get an accurate refrigerant reading. If your system is low on refrigerant the system will freeze up. If the system is low on refrigerant it may have a leak. A set of analog or digital refrigerant gauges will need to be connected to determine if the refrigerant is low. If the refrigerant is low you will have to check for leaks. Check the system very carefully of put in glow dye to determine exactly where the leak is. You can Repair the leak if possible and then add the correct amount of refrigerant.

homeowners and technicians alike typically assume the system is low on refrigerant. Don’t just assume this. Do your due diligence and make sure the rest of the system is clean and functioning correctly. An HVAC system very well may be low on refrigerant however, even if it is it will not operate to its full potential if the system isn’t clean.

A Bad TXV Or Piston May Be Causing Your Air Conditioner To Ice Up

Why Does A Air Conditioner Ice Up And How To Fix It
TXV refrigerant metering device
Why Does A Air Conditioner Ice Up And How To Fix It
piston metering device

If the TXV or piston is bad it will need to be replaced. I use my digital gauges to determine if the metering device is restricted or not opening correctly. Depending on the brand of the coil and the location of the system this can be a difficult repair. Some of the metering devices are internal and some are external. The external ones are easier.

I have found after running thousands of service calls that the reason an air conditioner is icing up is typically not a major part that needs to be replaced.

Why Does A Air Conditioner Ice Up And How To Fix It if its a heat pump?

Some people aren’t aware they have a heat pump condenser instead of a straight cool air conditioner. If this is the case your outdoor condenser may be icing up because of a bad defrost board. When the air is cold outside, ice can build up on your heat pump’s condenser unit.

Your defrost control board monitors the sensors that test your system for ice and activate the defrost mode. The Defrost mode melts the ice that forms on your heat pump’s condenser coil.

Having light frost on the heat pump coils is okay if it’s cold. However, if the coils are extremely iced up with thick ice then your defrost board may be bad.

The heat pump has sensors that monitor the temperature of the coils. If they ice up the defrost board will activate so the coil won’t ice up too bad. The defrost board is located inside the control panel of the outdoor condensation unit. The defrost board isn’t very difficult to replace.

I hope You have found some useful troubleshooting tips from this post. If so please leave me a comment.

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