Grant Aerona R290 fault codes

16 codes from the Grant manual for the Aerona R290 heat pump. Pick one for what it means, the likely causes and where to start.

Code	What it means
1	Pump over-voltage protection
2	Pump under-voltage protection
3	Pump over-current protection
4	Pump light-load protection
5	Pump phase loss protection
6	Pump block protection
7	Pump over-temperature protection
E01	Connection fault between wiring centre and heat pump
E34	AC input voltage is abnormal
E35	Drive EEPROM error
E36	Power off reset
E37	Reserved
E38	Reserved
E57	Gas sensor offline
E58	Gas sensor
P01	Air in system or low water level