Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to DC Volts 
Drain primary system water from boiler until no pressure is in system
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
With no pressure in system measure the DC voltage across the red lead
(pressure sensor connector) and terminal 2 (blue) main terminal block.
Expected voltage approximately 0.0 Vdc.
Note.
1. Terminal 1 of main terminal block is the top connection when facing appliance front.
2. A fault code may be displayed due to no system pressure, this will not affect test results.
(pressure sensor connector) and terminal 2 (blue) main terminal block.
Expected voltage approximately 0.0 Vdc.
Note.
1. Terminal 1 of main terminal block is the top connection when facing appliance front.
2. A fault code may be displayed due to no system pressure, this will not affect test results.
Isolate as per TOPs P4
and refit as necessary