Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Isolate cold feed to boiler
Drain DHW circuit
Disassemble DHW flow manifold

Observation:

Inspect the DHW flow group components, manifold for:
  • Any restrictions and/or blockages
  • Impellor is free to rotate
  • Impellor damage
    Note:
    It is possible to disassemble flow group in situ.