Reasons for Ice formation in Split AC with their Solution

If you see ice building on your AC, the first thing you should do is switch off the appliance and let the ice melt away.

Then start the AC again after some time and if the ice reappears then you have some issue.

There are many reasons which can cause your air conditioner to work improperly and build ice.

Depending on the reason, ice may build upon 

  • indoor evaporator coil 
  • outdoor unit pipes 
  • Both indoor or outdoor unit
  • Accumulator

To solve your problem you need to identify the actual cause. 

Below are the reasons which may cause ice formation on your AC.

1. Low Refrigerant Gas 

IndicationLow Gas Level
EffectIce build up on evaporator coil
ProbabilityHigh
SolutionGas Refill

In this case, ice starts to build on the evaporator coil inside the indoor unit.

This is the most common reason amongst all.

You cannot manually check whether your AC has low gas or not.

You need a device for checking the gas pressure for finding out low gas levels, this can be done by an AC technician.

So call for a professional.

If this is the case for your AC then make sure to check gas pressure at the time of refilling or you may get fooled.

2. Faulty Temperature Sensors or Thermostat 

IndicationCompressor runs continuously
EffectIce build up on evaporator coil
ProbabilityModerate
SolutionRepair or Replace

The temperature sensor which is near the evaporator coils senses the indoor room temperature.

Ideally, the compressor should switch OFF after the desired room temperature is achieved.

If this sensor is faulty then it will fail to monitor or send the room temperature readings making the compressor to run always.

The same goes for a faulty thermostat.

In case of a faulty temperature sensor, you need to repair or replace it.

3. Faulty PCB Relay

IndicationCompressor runs continuously
EffectIce build up on evaporator coil
ProbabilityLow
SolutionRepair or Replace

PCB relays work like a switch and directs power to the compressor.

If it gets faulty and makes the power to the compressor direct then the compressor will never shut down and run continuously.

Continuous running of the compressor can lead to the formation of ice on the evaporator coil.

Only a trained technician can check if the PCB relay is damaged or not.

4. Choked Filters

IndicationDirty Filter
EffectIce build up on evaporator coil
ProbabilityModerate
SolutionClean the filters

A dirty filter choked with dust particles reduces the airflow.

To cool the room the air needs to be circulated with the coil. 

If the air filter is dirty then the airflow will get restricted causing ice formation and reduced cooling.

It is not necessary that ice will buildup in such a case but it is possible with moderate levels of humidity.

You can clean the air filter yourself.

5. Fan not Working

IndicationReduced or Nill Airflow
EffectIce build up on evaporator coil
ProbabilityModerate
SolutionReplace the Fan capacitor

If the indoor fan stops working, this will stop the air circulation in the room with the AC.

If there is no air circulation then there will be no cooling of the room, the temperature sensor won’t be able to check the room temperature, and the compressor will keep on running.

Eventually leading to ice formation.

Often the fan capacitor needs to be changed in such a case.

6. Bend in Suction or Discharge Pipe 

IndicationBend Pipe
EffectIce formation on the pipe
ProbabilityLow
SolutionRepair or Replace the pipe

The two wires which connect the outdoor and indoor unit called the suction and discharge pipe carries refrigerant.

If this wire gets bent from some point then it will restrict the flow of the refrigerant leading to unwanted results like ice formation or poor room cooling. 

Ice can form on these pipes near the outdoor unit.

In most cases, a bent pipe can be found very near to the outdoor or indoor unit.

The bent pipe needs to be fixed for proper flow. It can also be replaced with a new pipe.

7. Clogged Capillary 

ProbabilityLow
SolutionCapillary Cleaning

The outdoor unit of the air conditioner has a capillary whose function is to maintain gas pressure.

If this capillary is clogged with dirt or oil, then it may cause low pressure which is also caused by low gas level.

Similarly to low gas levels, this may lead to ice formation. Mostly it leads to ice formation on the outdoor unit cables.  

Only an expert technician can identify and solve this issue.

8. Faulty Accumulator

IndicationIce Forms only on the Accumulator
ProbabilityLow
SolutionReplace the Accumulator

An accumulator is a device that is connected between the compressor and the indoor evaporator coil.

The main function of this device is to protect the compressor from the liquid refrigerant. It allows the refrigerant to pass only in a gas or mist state.

If you observe that ice is forming only on this device and not on the other parts of the AC, this means the filter inside the accumulator is faulty.

You need to replace the accumulator in such a case.

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