I have H70 error on my LA-MI heat pump. What does this mean?

Modified on Tue, 07 Feb 2023 at 03:47 PM

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

Require additional help? Please follow link below


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