110V system not powering on (new install or previously working)

Short answer: start by measuring the voltage between L and G at the outdoor unit. It should read 110V. 0V means a power supply or wiring problem; 110V with no response points to a control board, display or remote. These checks must be done by a certified HVAC contractor or electrician.

New installation that has never powered on

1. Check the power requirements on the nameplate on the right side of the outdoor unit. All 110V systems need a single-pole breaker with one hot wire, one neutral and a ground.
2. Measure L to G with a multimeter set to AC voltage. It should read 110V. 0V means no power is reaching the outdoor unit: check the wiring and the disconnect box, then confirm the panel is supplying 110V. Have an electrician correct any discrepancy.
3. If you have 110V, check the indoor unit. Press the auto-cool button once (sets 76°F / 24°C) and listen for a beep. If the display doesn't light, disconnect and reconnect it; if it still doesn't light, the display may need replacing.
4. If the display works, check the remote batteries and try again. If the unit still doesn't respond, the remote or the infrared receiver on the display may be faulty.

System that was working and stopped powering on

This is often caused by a power outage, lightning strike or surge, which can damage the outdoor control board and stop power reaching the inverter board.

• 110V between L and G: the outdoor control board is likely faulty and may need replacing.
• 0V: the problem is the incoming power supply. Have an electrician inspect it, as a surge may have caused other damage.

Order a part or get help

Submit a support ticket with your voltage readings, a photo of the model/serial label (where to find it) and whether the system ever worked.

Have a 220V system? See 220V system not powering on.