Common Causes
- Dirty air filter or blocked outdoor unit
- Low refrigerant charge
- Reversing valve stuck in heating mode
- Frozen outdoor or indoor coil
- Thermostat configuration issue
What You Can Try
- Check and replace the air filter.
- Clear debris from around the outdoor unit.
- Confirm the thermostat is set to "Cool."
- If cooling still isn't working, shut the system down and schedule a repair — a stuck reversing valve or refrigerant leak needs a technician.
If these steps don't resolve the issue, stop troubleshooting and call a licensed technician — repeated restarts or DIY repairs on gas or electrical components can be unsafe.
