Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Disconnect leads from the air pressure switch noting the connections
Remove tube from front connector on APS
Remove tube from front connector on APS
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. (rear connector of APS)
Increase the pressure via the syringe to that indicated on the pressure switch
Measure between common and normally open terminals on the air pressure switch. (terminals 1 and 3).
Expect continuity / zero resistance.
Note:
If continuity is not obtained when the specified pressure
is applied 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. (rear connector of APS)
Increase the pressure via the syringe to that indicated on the pressure switch
Measure between common and normally open terminals on the air pressure switch. (terminals 1 and 3).
Expect continuity / zero resistance.
Note:
If continuity is not obtained when the specified pressure
is applied 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