Set Appliance State:
Mains Power Off
Set Multimeter to DC Volts 
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Apply heating demand, allow fan to start and burner to establish.
Remove CH demand (turn boiler stat to Off) check for voltage across red and black connections on the gas valve as the appliance shuts down.
Warning: 200V DC may be present.
Remove CH demand (turn boiler stat to Off) check for voltage across red and black connections on the gas valve as the appliance shuts down.
Warning: 200V DC may be present.
Isolate as per TOPs P4
and refit as necessary