Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to AC Volts 
DHW Demand
Disconnect HW OFF wire from timer back plate and make safe
Refit timer to back plate
Turn Cylinder Thermostat to its MAX setting
Refit timer to back plate
Turn Cylinder Thermostat to its MAX setting
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Measure the voltage on the right hand terminal block between the connections marked "sL" and "N".
Is mains voltage still present?
Is mains voltage still present?
Isolate as per TOPs P4
and refit as necessary