Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to DC Volts Set meter to measure DC Volts
Gain access to PCB (use Insulation Mat as required)
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Measurement:

Measure for DC voltage across pin14 (red lead) of connector X2 and a suitable earth connection.
The voltage measured will vary according to the primary system pressure but should conform approximately to the table below;
Voltage (DC)Approx. system pressure (bar)
1.20
1.71
2.22
2.83

Is the voltage measured 1.0 Vdc or greater?
Note: Pins are numbered on the connector.