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The Daily Insight

Why does my heater work but my AC doesnt?

Author

Rachel Ross

Published Feb 08, 2026

Why does my heater work but my AC doesnt?

A Faulty Thermostat Try turning on the thermostat and adjusting the temperature so that your HVAC is turned on. If it fails to come on, check the circuit breaker and ensure that the switch is functioning properly. If you find that it had tripped, turn it back on. This should fix the problem.

What does it mean when your AC unit is not running?

After some investigating, you determine that your outside AC unit isn’t running but the inside is. Typically, this means one of two things: your outside AC hums but the fan doesn’t spin or the entire outside AC unit isn’t working at all. What could be causing either of these problems, and, more importantly, what can you do about it?

Is the condensing unit connected to a crankcase heater?

Receivers are often incorporated into refrigeration system condensing units. Within the condensing unit, the compressor will often have a heater connected in some way to its bottom section or crankcase. This heater is often referred to as a crankcase heater (see Figures 1 and 2).

Why does my outside AC compressor shut down?

If the outside unit gets too dirty, your AC compressor could overheat. This could cause the unit to shut down. It’s also possible that a safety switch has locked the outside unit of your home’s AC system. If this happens to be the case, a simple reset will bring it back to normal.

What should I do if my heater is not working?

If your heater’s controls seem to be faulty, first unplug the unit and plug it back in to see if that resolves the issue. Next, check the heater’s thermostat (if it has one) and make sure it’s set to the correct setting. Try resetting it to see if that fixes the problem.

Why is my central air heater not working?

There is No Gas – Heater Not Working. The central air system requires several different power resources. It uses gas, electricity and even water. Consequently, it is easy to lose track of what is on and what is off. Sometimes, homeowners call AC technicians about a problematic furnace only to discover that the power breaker was off.

Why is my gas heater not working when the thermostat is on?

This can be because the gas valve is stuck or the control board is unable to communicate. In these situations, the furnace is ready for heating, but because it is unable to build a flame, it cannot proceed with the process. If all other gas appliances in your home still work, you may need to call an electrician to help troubleshoot.

Receivers are often incorporated into refrigeration system condensing units. Within the condensing unit, the compressor will often have a heater connected in some way to its bottom section or crankcase. This heater is often referred to as a crankcase heater (see Figures 1 and 2).

What causes an outside AC unit to shut down?

If the outside unit gets too dirty, your AC compressor could overheat. This could cause the unit to shut down. It’s also possible that a safety switch has locked the outside unit of your home’s AC system. If this happens to be the case, a simple reset will bring it back to normal. Within ten minutes, the outside unit should begin working again.