Article reference KA-01359

Applicable to models: LA6MI, LA9MI, LA12MI, LA16MI
Issue: Error code H64 shown on the display. No heat, compressor is stopped.
What this means: H64 error is due to a refrigerant high pressure abnormality.
Until an engineer can attend, it should still be possible to use the electric backup. To enable the backup search for the guide "How to I switch on the backup on the LA-MI heat pump?" on the GDHV Help Centre.
Action: Engineer will need to investigate by following the flow diagram below.
Note that only F-GAS qualified engineers are legally allowed to work on the system if they are leak checking or changing refrigerant components!

Malfunction Decision Conditions:
During operation of defrosting and heating, when the outdoor high pressure sensor output signal is 0Vdc or 5Vdc.
Malfunction Caused:
1 Faulty connector connection.
2 Faulty sensor.
3 Faulty outdoor unit PCB (main).
Abnormality Judgment:
Continue 4 times in 20 minutes.
Location of connector & sensor on LA6MI / LA9MI Refrigerant PCB:

Location of connector & sensor on LA12MI / LA16MI Refrigerant PCB:

Possible parts required depending on engineers diagnosis:
• High Pressure Sensor
LA6MI / LA9MI / LA12MI / LA16MI part: X-2511012
• Main Refrigerant PCB (part number depends on model of heat pump)
LA6MI part: X-2511024
LA9MI part: X-2511038
LA12MI part: X-2511044
LA16MI part: X-2511057