Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to DC Volts 
ON/OFF switch ON
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Measure for dc voltage across connections 12 (green) and 1 (black) on
the connector X2
This voltage will vary according the boiler system pressure.
Note:
Approx voltage should be between 1.7 - 1.9 volts dc.
the connector X2
This voltage will vary according the boiler system pressure.
Note:
Approx voltage should be between 1.7 - 1.9 volts dc.
| System pressure | Voltage dc | 0 bar | 1.2 |
| 1 bar | 1.7 |
| 2 bar | 2.2 |
| 3 bar | 2.8 |
 pressure guage.gif)
Isolate as per TOPs P4
and refit as necessary