Isolate Mains Power to appliance as per TOPs P4
Remove diverter valve head
With head removed actuator pin should be fully retracted
Remove diverter valve head
With head removed actuator pin should be fully retracted
Observation:
Is actuator pin fully retracted into the DHW position?
Refit diverter valve head after test.
Refit diverter valve head after test.
Isolate as per TOPs P4
and refit as necessary