Why Your HVAC System Won’t Stay On (2024)

FAQs

Why Your HVAC System Won’t Stay On? ›

Some other reasons your HVAC system won't stay on due to short cycling are incorrect sizing, frozen coils, low refrigerant due to a leak, a faulty compressor, or malfunctioning control board. These issues require the help of a professional HVAC technician to fix through heating repair.

Common Causes for AC Short-Cycling

Clogged air filters. Electrical problems. Thermostat issues. Dirty coils or frozen evaporator.

If the wiring between the AC and the thermostat is faulty, or if the thermostat is miscalibrated, your AC may begin to short cycle. Your thermostat may not properly register the temperature inside your home, forcing the AC to repeatedly start and stop in order to reach the desired temperature.

Change your filter – Dirty filters are often the culprit of poor AC performance. It adds resistance and reduces airflow. Make sure outside condenser coil is clean – clear of cottonwood and other debris. Clean out condensate drain lines – make sure they are clear of debris.

If your AC unit is turning on and then off right away, there are several possible causes. These include thermostat problems, refrigerant leaks, oversized AC units, and dirty air filters. With the exception of a dirty air filter, most of these issues should be addressed by a qualified HVAC technician.

AC Problems that Cause Your Unit to Shut Off

Unit is overheating – This usually indicates that there is grime buildup within the compressor, but it could also be indicative of a more complex refrigerant leak. Faulty thermostat – The wiring may have been damaged on your thermostat, or there may be an electrical problem.

Insufficient airflow into the furnace

For the burners to ignite, they need airflow. The airflow into the furnace comes from the blower fan that draws air through the return air ducts. But if this airflow is choked off because of a clogged furnace filter or faulty blower, the burners may not be able to stay on for long.

As mentioned, one of the more common reasons for an AC unit needing a reset is due to the protection circuit breaker inside the unit kicking in. This usually happens after a power outage occurs, and this failsafe is in place to prevent fires and explosions from occurring from a power surge.

How cool should my house be if it's 100 outside? ›

For many of us, 70 degrees is the ideal indoor temperature, but when it is close to 100 degrees outside, your AC unit will be working quite hard to meet these expectations. Consider setting your thermostat at 75 degrees to 80 degrees in your home if the outside temperature is approaching triple digits.

A dirty air filter is one of the most common issues affecting the performance of household HVAC systems. Fortunately, a dirty filter is one of the easiest problems to fix. Your air filter should be changed on a regular basis.

When the temperature soars, your AC has to work harder to maintain a comfortable indoor climate. It needs to remove more heat from your home, and if it's not properly maintained or appropriately sized for your space, it can struggle to keep up.

There might be a simple reason behind an AC that keeps turning off–dirty air filters. The air in your home carries dirt, dust and debris, and the air filter traps all these particles. But it can become clogged over time, and when that happens, it can cause the unit to short cycle.

Your AC unit turning on and off repeatedly is one of the most common AC problems homeowners face. It can be caused by dirty, damaged, failing components or electrical and mechanical factors. If your AC unit keeps turning on and off repeatedly, then it's probably experiencing short cycling.

Short Cycle Reason: Dirty Filter Obstructs Airflow

When these components overheat, the system must shut down, resulting in a short cycle. If you ignore an air conditioner that stops and starts due to a dirty filter, you risk permanent damage or major air conditioner repairs.

If your air conditioner keeps running when it's turned off this could be a sign of shorted thermostat wiring. A continuously running air conditioner could also be triggered based on the settings selected for the unit.

One of the most common reasons why your AC fan is not spinning is because the thermostat is not set correctly. Be sure the system is set for cooling and not heating and then switch it back to cooling or auto mode and check that the appropriate cooling temperature is selected.

Your Thermostat Isn't Working Properly

Similarly, thermostat problems are another possible reason that air blows while your AC is off. Like the other parts of your HVAC system, your thermostat can wear down over time and require repairs.

Common Reasons Why Your Air Conditioner is Not Turning On

Resetting your thermostat is often all that's necessary to get it working again. A tripped circuit breaker is another common reason why your AC won't turn on. Using too many appliances at once can trip the circuit breaker.