Why Is My AC Compressor Keeps Cycling on and Off Every 10 Seconds?

Your AC compressor should typically run for approximately 10 minutes before shutting off. If yours keeps cycling on and off every few seconds, however, this indicates it is not cooling efficiently.

Low or high refrigerant pressure could be to blame, which you can measure with a set of gauges.


Compressors are one of the key components in your car’s air conditioner system, serving to take refrigerant from its source evaporator, compress, heat and liquefy it for distribution throughout your vehicle. Furthermore, compressors transfer cooled refrigerant back out into the atmosphere via condensers for dispersion into the atmosphere outside your vehicle.

An efficient AC unit typically features a 20-minute cooling cycle. If your unit switches on and off every 10 seconds, professional assistance should be sought to examine its compressor.

If your compressor is short cycling it could be the result of refrigerant leakage. Other issues could include faulty compressor clutches or expansion valve clogging; left unaddressed these problems will reduce AC efficiency significantly and render your air conditioning less effective than it once was.

Another possible explanation for why your compressor may be cycling on and off frequently is due to overpressurization, with high-side pressure being defined as the area between compressor discharge and evaporator inlet. Therefore, it’s crucial that any refrigerant leaks be discovered immediately and that all necessary parts like clutch, pressure switch and run capacitor are in good working order as this could contribute to overworked compressors. Furthermore, your air filter must also be regularly maintained since a dirty one could put additional strain on an already overworked unit!


Your compressor is at the heart of any air conditioning system. It takes gaseous refrigerant, compresses it, superheating it in the process and liquefies it to form coolant that your evaporator uses for cooling purposes.

Compressors work similarly to car engines: their motor drives up to eight pistons inside an airtight cylinder block that move in unison, drawing in gaseous refrigerant and compressing it.

Over time, the compressor can experience issues which cause it to short cycle, such as an expansion valve clogged by dirt and other debris. When this occurs, compression does not take place properly and high pressure results. As a result, the compressor shuts down in order to stop this from occurring before restarting when pressure equalizes again.

Problems may also stem from the compressor clutch, which could be worn out or have become loose; should this be the case, its actions could cause it to continue switching on and off as the compressor attempts to overcome this challenge.

Signs that your compressor may be starting to fail include cold or lukewarm air coming out of its vents when it is turned on, or whether or not hot air is being released externally from its vents. To verify whether or not your compressor is functioning normally, observe whether hot air is being expelled externally from its compressor.


Your compressor serves a vital role in an AC system, connecting the evaporator coil on top of your furnace with the condensing coil in its box containing it. By pumping refrigerant from evaporator coil to condensing coil, and increasing temperature and pressure within its box, this allows refrigerant vapors to turn back into liquid state for recycling back through discharge line back to evaporator coil.

Evaporator coils serve to absorb heat from indoor air in homes and then pump it outdoors to condenser units where it’s released as refrigerant vapor, only then is it back through to evaporator coils for another round of absorption and release of heat. Once complete, this cycle repeats itself again until no heat remains stored within its liquid state and back again to the evaporator coil for consumption by warm air passing over it.

Frozen AC components like its evaporator coil or condenser could prevent its compressor from operating normally and is an indication that there may be serious problems with your air conditioning unit, requiring professional intervention to resolve. Call an HVAC specialist immediately so they can address these issues before they cause further damage.

Faulty air conditioning system components like insufficient or excessive refrigerant pressure may also contribute to short cycling, using a pressure gauge to detect under or over-pressurization. Other issues include clogged components and compressor clutch noises that need to be addressed; you’ll need to inspect expansion valve, compressor clutch and evapator components in order to detect these problems.

Pressure Switch

Air conditioning compressors may short cycle for various reasons. One of the more obvious causes is low refrigerant pressure, which can easily be checked using a simple pressure gauge. Other potential sources for short cycling could include bad compressor clutches, clogged expansion valves or incorrect refrigerant charges.

An AC system utilizes a high and low pressure switch to closely monitor air pressure. Once pressure reaches a predefined threshold, the switch will activate and turn off the compressor – this is to prevent its overheating.

Pressure switches are two-part devices made up of a pressure sensing transducer and electrical switch. The pressure sensor often contains diaphragms for pressure sensing; its setpoint can be altered using springs. Finally, its electrical contacts allow current to pass from an external power source.

The hoses attached to a pressure switch should be in good condition and match connection sizes; using a multimeter, check voltage on its contacts; otherwise a faulty pressure switch could give false readings that turn the compressor on and off repeatedly – in this event it must be replaced immediately.