Set Appliance State:

Mains Power Off
CH Demand
Boiler Thermostat set to its '0' position
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Is the water pump running?
Note:
1. Do not take sound or vibration as an indication of the pump running.
2. Ensure the selector switch is in the correct position for the type of system the appliance is fitted to.