Set Appliance State:

Mains Power Off
Set Multimeter to DC Volts Set meter to measure DC Volts
Remove control box cover
Remove and MAKE SAFE one wire from the M5 - "Room Stat" terminal
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 "Room Stat" terminals of M5, if this is the case for this test remove one side of the link.
Measure DC voltage across the terminals of M5 marked Room Stat on the PCB.
Expect approx. 24Vdc across the terminals.
Reconnect the wire after testing.