Set Appliance State:
Set Multimeter to DC Volts 
Isolate Mains Power to appliance as per TOPs P4
Gain access to PCB connections as necessary
Gain access to PCB connections as necessary
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Measure voltage across connection 4 ( +ve probe to yellow lead) and connection 1 (-ve probe to black lead) on connector J11 on the control PCB.
Voltage will vary according to the boiler system pressure but
should conform approximately to the table below:
Voltage will vary according to the boiler system pressure but
should conform approximately to the table below:
| System Pressure | Voltage DC |
| 0 bar | 0.5 |
| 0.4 bar | 0.8 |
| 0.8 bar | 1 |
| 1.2 bar | 1.2 |
| 1.6 bar | 1.6 |
| 2 bar | 1.8 |
Isolate as per TOPs P4
and refit as necessary