Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Disconnect plug connector (marked ST16) from PCB
Measurement:
Note the operating pressure indicated on the pressure switch.
Connect the air pressure switch charge kit to +ve connection on the air pressure switch.
Increase the pressure via the syringe to that indicated on the pressure switch. Continuity (zero resistance) should then be measured across connections 14 & 15 (green wires).
Note:
35 CDi II appliances may have APS fitted inside combustion chamber next to fan.
If continuity is not obtained it is permissible to increase the pressure by 50%.
100 Pascals = 1mbar / 50 Pascals = 0.5mbar
Connect the air pressure switch charge kit to +ve connection on the air pressure switch.
Increase the pressure via the syringe to that indicated on the pressure switch. Continuity (zero resistance) should then be measured across connections 14 & 15 (green wires).
Note:
35 CDi II appliances may have APS fitted inside combustion chamber next to fan.
If continuity is not obtained it is permissible to increase the pressure by 50%.
100 Pascals = 1mbar / 50 Pascals = 0.5mbar
Isolate as per TOPs P4
and refit as necessary