Daikin Altherma fault H6-00

What it means

Compressor fails to start within 15 seconds after the compressor run command signal is sent.

Likely causes

1. Faulty or disturbance of the power supply (power supply MUST be within range of nominal operating voltage ±4%)
2. Faulty compressor or miswiring of the compressor power supply cable
3. Closed stop valve in the refrigerant circuit
4. Clogged refrigerant circuit
5. Refrigerant overcharge or shortage
6. Non-condensables and/or humidity in the refrigerant circuit
7. No power supply
8. Damaged or broken wires between power supply terminal and hydro PCB

Where to start

1. Check if the power supply is compliant with the regulations per section 4.1 Electrical circuit
2. Check that all stop valves of the refrigerant circuit are open
3. Check if the refrigerant circuit is clogged