Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Remove APS from boiler
Measurement:
Note the operating pressure indicated on the pressure switch.
Connect the air pressure switch charge test kit to the + connection on the air pressure switch.
Increase the pressure via the syringe to that indicated on the pressure switch.
Continuity should then be measured between common and normally open terminals of the air pressure switch.
Note :
If continuity is not obtained, it is permissible to increase the pressure by 50%.
100 Pascals = 1mbar / 50 Pascals = 0.5mbar.
Reconnect air pressure leads after test completed.
Connect the air pressure switch charge test kit to the + connection on the air pressure switch.
Increase the pressure via the syringe to that indicated on the pressure switch.
Continuity should then be measured between common and normally open terminals of the air pressure switch.
Note :
If continuity is not obtained, it is permissible to increase the pressure by 50%.
100 Pascals = 1mbar / 50 Pascals = 0.5mbar.
Reconnect air pressure leads after test completed.
Isolate as per TOPs P4
and refit as necessary