When you have a problem with your HVAC system turning on and off without changing the temperature in your home, this is called short cycling. If you are cooling your home and your air conditioning is short cycling, low refrigerant levels may be the cause. You might hear your air conditioning turn on, but turn back off before your home has been cooled. When it is your furnace that is short cycling and your home won't get warm, a dirty filter or problems with a blocked exhaust vent could be causing your furnace to turn off before your home is hot enough. Pay attention to system problems, and call your HVAC system services when you can't get your home to the right temperature.
Problems with the Thermostat
One of the easiest fixes to your heating or cooling system is when the thermostat isn't working properly. Your heat or air conditioning can both turn off prematurely if your thermostat is broken and not measuring the temperature in your home correctly. Check that your thermostat is set to cool or heat, depending on your needs. Sometimes it gets set to fan, which won't do anything but circulate the air in your home.
Ice On Evaporator Coils
The evaporator coils on your air conditioning unit can become iced up, causing the system to have poor airflow. Ice can develop when you have low refrigerant levels, or when moisture gets on your evaporator coils and starts to build up ice. Start by turning off your air conditioning and allowing the ice to melt completely. If you turn the system back on and the ice builds back up again, you will need HVAC system services to repair your air conditioner. The ice can cause your air conditioner to short cycle.
Clogged Air Filters
Clogged air filters can make it impossible for your HVAC system to run without straining. If the filter is too clogged, your furnace or your air conditioning will shut off before it completes a cycle. Change the air filters on your furnace or your air conditioning if you are having issues with short cycling and see if this solves the problem.
Temperature control in your home is often an ongoing process. HVAC services technicians will take a look at your furnace or your air conditioner, depending on which system is not functioning correctly. You can try changing air filters, and making sure your thermostat is set correctly. When your system keeps short cycling, it's time to call for service.