AC Short Cycling: 6 Causes & Fixes

One will know an air conditioner to be short cycling when it turns on and off between very short intervals of time. Usually, on a very hot day, the running cycle of an AC is ten to twelve minutes and on slightly colder days, this break will be longer.

You have probably noticed a whirring sound coming from the outdoor unit of the AC and the sound starting and stopping on its own. Well yes, that is the run time or running cycle of a healthy AC.

The problem begins when this running time decreases due to whatever reasons and the AC turns on and off more frequently. This is what they call a short cycling AC.

This is not a light or a minor problem and should not be treated as one because the AC unit constantly turning on and off exerts quite some pressure on the compressor and if allowed to continue this might damage the entire AC unit.

What Is AC Short-Cycling?

An AC runs in a succession of cooling cycles which is the collected warm air being passed through the refrigerant gas which absorbs the latent heat thus cooling down the air which is then distributed into the room through the vents. This entire process is one cycle and occurs while the compressor is on.

Depending on the weather, an average cooling cycle lasts for ten minutes. After which it stops for ten minutes and then turns on again. This process is repeated two more times in one hour.

But when the duration of these ten minutes is shortened to say, three or four then it exerts pressure on the compressor which is being forced to turn on and off more frequently. This is called AC short cycling. This may strain the compressor and cause it to wear down sooner because of the short cycling AC unit.

How do you know if AC is short cycling?

There are a few different ways to tell if what you have at hand is an AC short cycling or something else.

  • The unit shuts on and off rapidly and between short intervals.
  • The space is not cooled to the set temperature on the thermostat.
  • The cooling is not sufficient, that is the temperature is warmer than it should be,
  • The pressure or flow of air from the vents is weak, even at the highest fan setting.
  • The energy bills show a higher number than they should be.

6 Causes of AC short cycling and How to Fix It

AC short cycling

As has been mentioned before, a short cycling air conditioner unit exerts much pressure on the compressor and therefore the root cause of the problem should be fixed at the earliest to avoid any further damage to the compressor.

An AC unit short cycling may be caused due to a number of reasons. Some of the most probable ones have been listed below.

Dirty Air Filter

The role of an air filter is to purify the air by ridding it of solid debris and other components such as dust, pollens, allergens, etc.

That means it is inevitable that the filters get dirty and clogged. If such a thing happens then a number of issues can crop up inside the AC including the problem of short cycling.

Solution: If something dirty is giving you trouble then you have to clean it. Cleaning dirty AC filters is not a big deal at all. The hard part is identifying where in the AC the filter goes in because it may be different for some models. Usually, the filters are slid into the top part of the AC after you put up the AC cover.

Bring out the filters and clean them with water or simply dust them with a brush. Make sure to dry them completely before putting them back in if you wash them with water.

Frozen Evaporator Coils

This is almost a direct consequence of dirtied and clogged air filters. When the filters are blocked. The air that cannot pass through because of a barrier of dirt and cannot find an exit ends up freezing the refrigerator coils.

This is hardly an ideal situation because those coils are responsible for collecting the warmth from the air inside your home and when it cannot do that it goes into overdrive mode and starts to short cycle because of the anomaly in the internal temperature of the coils itself.

This can happen for either dirty filters or a lack of regular maintenance.

Solution: In any case, the most important matter at hand is to get rid of the layer of ice from the evaporator coil and the good news is that you can do it at home.

The coils are located just near the vents, just hold a blow dryer or a hair at the lowest heat setting near it. The ice will melt and drip from the vent in trickle gradually. Hold the stream of warm air until there is no more water dripping from the vent.

Check if this has solved the short cycling issue, if not, best call a professional to take a look.

Lowered supply of Refrigerant

The refrigerant gas stored inside all air conditioner units is one of the most important components of the whole system. Because this is responsible for performing the very role for which the AC is best known for- cooling down the air.

A refrigerant is a gas and is stored inside the AC coils in an airtight seal, that is to say, this gas does not act as a fuel and every AC unit receives a particular amount of refrigerant inside it while getting manufactured. This basically means that there is no way for the refrigerant gas to extinguish itself as it works in a closed loop to cool the air.

But sometimes, due to some damage on the surface of the copper coils housing the gas, there are cracks through which the gas may start leaking. If that happens, then the AC unit will not be able to reach the set temperature on the thermostat in its usual cooling cycle and cause short cycling.

The obvious signs of an air conditioner short cycling because of leaking refrigerant gas is the quality of air being emitted will be warm even at lower temperature settings. There may also be water leaking from the vent due to frozen evaporator coils.

Solution: There is no way that you can fix a short cycling air conditioner caused by a damaged evaporator coil and leaking refrigerant, all on your own. This is because the coil will have to be replaced and because the gas is toxic, volatile, and quite harmful if inhaled.

So if you suspect a refrigerant leak then it is best to turn the AC off and call a professional and make sure to check if you or anyone inside your house has inhaled the gas or not. Consulting a doctor just to be sure is also highly recommended.

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AC unit not compatible with the Size of the Space

Have you ever heard of the term “Ton” being associated with air conditioners? Well, it can be considered as a unit for measuring the cooling capacity of an AC. In other words, the term Ton is used to represent the amount of cool air the particular AC will distribute in a room.

The ton needed for a room depends on its size and that is why a seller will always ask you the dimensions of the room you will be placing it on to recommend you a compatible air conditioner. The most commonly bought is 1.5 Ton and it works well in most rooms of average size.

However, if it so happens that the cooling capacity of the AC exceeds the size of the room then what will ensue is a short cycling unit. This will happen simply because the AC will not need the entire duration of its one cooling cycle to cool a room of a small size.

It will cool the room faster and once the desired thermostat temperature is reached, it will shut down and then turn on again in quick succession.

Solution: You might have guessed but there is no foreseeable solution to this unless you plan to move the AC to a bigger room or replace it with one with a lesser ton. That’s about the only two things you can do other than freezing inside the room with a further lowered temperature on the thermostat.

A problem in the Electrical circuit or Wiring

Sometimes the cause for short cycling may not be related to the AC at all and may be a result of some fault in the electrical circuit or wiring. This will cause the air conditioner unit to randomly turn on and off without completing one whole cooling cycle.

Solution: There is only one thing you can do about this and that is to call a relevant professional, preferably an electrician. If you see that none of the other mentioned problems seem to be the case with your AC unit then faulty wiring is likely. The electrician has to make sure that the circuit you are connecting the Air conditioner to is even built for the device or not.

Placement of the Thermostat

Yes, it might seem unlikely but where in your house the thermostat is located can determine some things such as the problem at that, i.e, short cycling AC unit.

If the thermostat is located somewhere in the direct line of the sun then it will take into account the heat from the sunlight and misread the room’s temperature. If such a thing happens, it will turn on the AC and causes a short cycle.

Although obvious, it should be mentioned that a wrong placement of the thermostat will only cause AC short cycles during the day when the sun is still outside.

Solution: Well, you can consult with an electrician to move the thermostat to some other part of the house where it will not take into account the external temperature of the sunlight. Or if you think that moving the thermostat is too much of an hassle, just cover the window from where the sunlight is coming with a curtain.

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Final Words

Needless to mention again, a short cycling AC is indeed something you should sit on and make arrangements to fix it as soon as possible.

Because the more you let this problem be, the more it will damage the components inside the AC starting with the compressor and eventually the evaporator coil and then the whole unit.

Therefore, it is best to identify the problem and get to fixing it as soon as possible.

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