Common Heating and Air Conditioning Problems

By Terry Mehilos | Oct. 18, 2023 12:44 pm PST

Updated October 18, 2023.

Is your home too hot to handle? Or maybe it’s cold as ice. Here are some common problems that can occur with your HVAC (heating, ventilation and air conditioning) system.

Heating System Problems

No Heat

Check the thermostat to make sure it’s set for heat and the temperature setting is high enough to call for heat. Adjust the thermostat if it isn’t set properly.

If your thermostat is set properly, follow these additional DIY troubleshooting tips to resolve the heating problem.

  • Check the air filter and replace it if it’s dirty. A clogged air filter won’t allow air to flow through the heat exchanger.
  • If you have a gas furnace, check the cut-off gas valve on your gas supply line and make sure that valve is open.
  • If you have a heat pump, check the house circuit breakers for your HVAC system and reset any tripped breakers.

Check your owner’s manual and follow any additional troubleshooting tips for your heating system to restore heat.

If you’re unable to restore heat after following these DIY troubleshooting tips, it’s time to schedule heating system repair service.

Image person cold because the furnace isn’t heating

Not Heating Well

Check the thermostat settings. If the blower fan is set to run constantly but the temperature setting isn’t set high enough to call for enough heat, adjust the thermostat. If the thermostat isn’t working properly, replace it.

If the thermostat is set properly and working as it should, check the air furnace air filter. A dirty filter will block air flow through the heat exchanger and air vents in your home. Replace the air filter if it’s dirty.

If these tips don’t help, then a problem with the furnace burners or the blower fan could be causing the heating problems in a gas furnace. Sealed system or control problems could prevent a heat pump from heating well. Have a service technician examine and repair your heating system if you’re not able to restore proper heating.

AC Unit Failures

Not Cooling

When your central air conditioner runs but doesn’t cool, the problem could be caused by something as simple as bad thermostat settings. If the thermostat is set to run the fan constantly but the temperature setting isn’t low enough to initiate cooling, then you can fix the cooling problem by adjusting the thermostat settings. If the thermostat is faulty and won’t signal the air conditioner to start cooling, then you’ll need to replace the thermostat.

If thermostat settings are okay, the condensate drain float switch may be tripped because the condensate drain line is clogged and water is backed up in the drain system. Clear the clogged drain line so the float switch resets and allows the air conditioner to run. Here’s a DIY troubleshooting video that shows how to clear the condensate drain line.

If the condensate drain float switch isn’t tripped, then the outside compressor and condenser unit may not be working. Check to see if the condenser fan and compressor are running. If not, check the house circuit breakers for the outside unit. Resetting the house circuit breaker may restore cooling. A bad capacitor can prevent the compressor and condenser fan from running. Many AC systems use 1 dual capacitor to help start the compressor and condenser fan. If the capacitor is bad, you’ll need to have it replaced.

If the compressor and condenser fan both run, then lack of refrigerant or a bad compressor may be preventing the air conditioner from cooling.

Several other problems such as a wiring failure or a bad compressor fan motor can prevent the AC from cooling. If you’re not able to diagnose and fix a cooling failure yourself, have a service technician repair your air conditioner.

Not Cooling Well

When your central air conditioner is running and producing some cool air but not cooling down your home, check the air filter. A dirty air filter won’t allow air to flow through the evaporator in your air conditioner and the air vents in your home properly. Replace the air filter if it’s dirty.

If replacing the air filter doesn’t restore proper cooling, then check for blocked air flow through the condenser unit outside your home. The condenser coils cool down hot, compressed refrigerant before the refrigerant enters the evaporator. If condenser coils are blocked or clogged with dirt and debris, then the central AC won’t cool very well. Clear grass and vegetation from around the condenser. Have a service technician clean the condenser coils if they’re clogged with dirt and debris.

If these tips don’t help restore cooling capacity to your HVAC system, then low refrigerant charge, a faulty compressor or clogged evaporator could be preventing the central air conditioner from cooling properly. Schedule a service technician to diagnose and repair your AC system.

No Power

When your heating and cooling system has no power at all, check the house circuit breakers for your unit. Reset any tripped breakers for your HVAC system.

If resetting the house circuit breaker doesn’t restore power to the thermostat, then the thermostat may have failed. Replace the thermostat if it’s getting power but won’t power up. If you replace the thermostat and the air conditioner still won’t work, you’ll likely need to have a service technician examine and repair the air conditioner.

Trust Sears Home Services to help you get your heating and cooling system going again when you encounter problems. We have same day and next day HVAC repair appointments available in many areas so we can get your system fixed fast – and right.

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