Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Appliance Drained and Discharged

Observation:

Fully inspect the flow switch brass manifold and flow switch assembly.
Check for blockages and restrictions in the brass hydroblocks.
Also check the condition of the spindles and diaphragms.
Note:
Due to the position of the diverter valve body it may be necessary to inspect the diverter body using a mirror.