Set Appliance State:
Mains Power Off
Set Multimeter to DC Volts 
CH Demand
CH temperature control to maximum
DHW temperature control to minimum
CH temperature control to maximum
DHW temperature control to minimum
Remove control box cover
| WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure |
Measurement:
NOTE: If no time controls are fitted there must be a link fitted between the two "Room Stat" terminals of M5.
Measure DC voltage across the terminals of M5 marked Room Stat on the PCB.
Expect approx. 0Vdc across the terminals.
Measure DC voltage across the terminals of M5 marked Room Stat on the PCB.
Expect approx. 0Vdc across the terminals.
Isolate as per TOPs P4
and refit as necessary