Grant Aerona R290 fault 6

What it means

Pump block protection has activated; pump will automatically re-start after 5 seconds.

Likely causes

1. Pump rotor blocked or stuck
2. Impurities in pump
3. Poor pump performance
4. Fuse is burnt out
5. Connection to PCB is loose or disconnects
6. Pump failure
7. Too low voltage
8. Pump rotors are stuck
9. Gas in the pump
10. Inlet pressure too low
11. Flow regulators or restrictors fitted in circuit
12. Valves not fully open causing flow restriction
13. Outside air temperature at or below 6°C
14. System water temperature at or below 6°C
15. External electrical isolator switched to OFF position
16. Heat pump switched OFF at the controller
17. No demand from heating system controls
18. Outdoor temperature too high to call heat pump on (weather regulated zones)
19. Active error code present on controller
20. Outdoor temperature too high for weather compensated zones to call heat pump
21. Active error code on controller display
22. Insufficient flow rate through primary circuit
23. PWM circulating pump not modulating correctly
24. Blockage or air in primary circuit
25. Pump fault or blockage causing low flow
26. External electrical isolator switched OFF for extended period during cold weather

Where to start

1. Check pump rotor for free movement
2. Inspect for impurities/debris in pump
3. Check inlet water pressure