Article reference KA-01360
Applicable to models: LA6MI, LA9MI, LA12MI, LA16MI
Issue: Error code H70 shown on the display.
What this means: H70 error is due to the backup heater Over Load Protection device activated or disconnected.
Action: Engineer visit needed to investigate. Engineer should follow the flow diagram below.
Underlying cause is likely to be air lock or poor flow in water between heat pump & house or excessive inlet temp if OLP keeps tripping out.
Before carrying out any works, isolate the heat pump at the mains supplies!
Malfunction Decision Conditions:
During operation of indoor backup heater, when no power supplies to indoor backup heater or OLP open circuit.
Malfunction Caused:
1 Faulty power supply connector connection.
2 Faulty connector connection.
3 Faulty indoor backup heater overload protector (OLP).
4 Faulty indoor unit PCB (main).
Abnormality Judgment:
Continue for 60 seconds.
Possible parts required depending on engineers diagnosis:
• OLP thermostatic cut out switch
LA6MI / LA9MI / LA12MI / LA16MI part: X-2511030
• Main Water PCB (part number depends on model of heat pump)
LA6MI part: X-2511031
LA9MI part: X-2511039
LA12MI part: X-2511051
LA16MI part: X-2511058