Why Does My AC Keep Turning On and Off?

Are you finding your air conditioner turning on and off repeatedly? Short cycling is not a good sign. Read below for some of the most common reason this happens.

1. Thermostat Location 2. Refrigerant Leak 3. Dirty Condenser coil 4. A/C too big 5. Drain line restricted 6. Poor electrical connection

1. Thermostat Location

Your thermostat is just a heat-sensitive switch.

When the room temp warms up above the set temperature, a switch in the thermostat closes and save-thermostatsends control power to the unit to turn on your AC.

When the temperature drops below the set point, the switch opens and breaks power - everything shuts off.

Now because the thermostat reacts to temperature, where it is located makes a big difference on how quickly it cycles the equipment on and off.

Is your thermostat by a supply vent?

If the cold air from the system blows directly on the thermostat, it gives a false reading, and the AC system shuts down before the true room temperature is reached.

Now because the temperature in the room is still warm - the HVAC unit cycles on quickly.

2. Refrigerant leak

If the refrigerant in the system is low, the unit may be shutting off on a low-pressure safety switch.

Once the air conditioner cycles off, the pressure in the system equalizes, system pressure then increases enough for the system to kick back on and the unit short cycles.

If you see this happening - Shut the AC off. This is very damaging to your system. Call an HVAC contractor for repair.

3. Dirty Condenser coil

Similar to the reason listed above in that it may be short cycling on a (high) pressure safety switch. High-pressure switch shuts down the system if too much pressure is sensed in the condenser.

This can happen for a few reasons. Having a dirty condenser coil is one of the most common.

If the condenser coil is dirty, enough heat can not be rejected out of the refrigerant & this causes the pressure to rise in the system.

The high-pressure safety trips, AC unit pressures equalize, and then the whole cycle starts over again. Be sure to shut the unit off - again, this is very damaging to your system. Call a professional for repair.

4. A/C too Big

sizesAn oversized A/C will have a shorter run time than desired. The unit reaches temperature quickly and shuts down.

You want your air conditioner to run for a minimum of 10 minutes or longer.

This helps control humidity better for comfort and minimize the wear and tear on the equipment.

5. Drain line restricted

If water can not drain quick enough from the air handler because the condensate drain line is partially clogged, water can back up and trip the float switch.

The unit cycles off, water then completely drains, and the AC unit kicks back on again. Check to see if the drain needs to be cleared.

6. Poor electrical connection

Having an intermittent electrical connection in the control circuit is possible. This can be anywhere in the control (low voltage) wiring. Usually, though it is located at the thermostat or anywhere the wiring is spliced.

This can be tough to find at times because often you have to see the problem occurring when trying to make the repair.

Short cycling of your air conditioning unit is bad!

The rapid cycling of your AC equipment can cause a lot of damage to your unit.

It creates a lot of wear and tear, generates costly repairs, increases energy usage from the constant cycling, and decreases comfort in your house due to high humidity levels.

If you see your AC short cycling, we recommend that you shut it down and give us a call for a repair.

Air Zero serves all of Pinellas County Florida. Give us a call at 727-392-6111.