Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to AC Volts Set meter to measure AC Volts
For access behind the control panel
Release the fixing screw located at the top of the case front panel
and lift the panel upwards from its locating pins and then
forwards from the boiler. Remove the two fixing screws that
secure the control panel and lower the panel.
For access to the control panel components
Remove the five screws securing the rear cover and careful raise the cover from the control
panel. When replacing the cover ensure no wires are trapped and all the wiring is secured
secure with screws previously removed do not over tighten.
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Measurement:

Measure voltage across the connections marked 11 (purple lead) and connection
marked 12 (grey lead) on the connector marked X4.
Expected voltage mains voltage (230 volts AC).