Set Appliance State:

Mains Power Off
Set Multimeter to DC Volts Set meter to measure DC Volts
CH Demand
CH temperature control to maximum
DHW temperature control to minimum
Remove control box cover
ON/OFF switch in the ON position
WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure
Mains Power On

Measurement:

NOTE: If no time controls are fitted there must be a link fitted between the two "Timer" terminals of M5.
Measure DC voltage across the terminals of M5 marked Timer on the PCB.
Expect approx. 0Vdc across the terminals.