H7 - Driver out-of-step protection

What does H7 mean?

This error occurs when the processor cannot detect the compressor rotor position, or the running speed does not match the commanded speed. Compressor operation stops. This is shown on the ODU main board LED.

• Compressor 3-phase wire connection is out of phase or phase-reversed
• Compressor wiring is out of phase
• System is blocked, short of refrigerant or compressor oil
• Drive board IPM module is damaged
• Drive board compressor current sampling circuit element is damaged
• Compressor is damaged

Click steps to track your progress.

1. 1

   Check the compressor 3-phase wire connections for correct phase sequence. Reconnect wires if phased incorrectly or out of phase.

2. 2

   Inspect the system for blockages, low refrigerant, or low compressor oil. Address these issues if found.

3. 3

   Replace the drive board if its IPM module or current sampling circuits are damaged.

4. 4

   Replace the compressor if it is damaged.