Set Appliance State:
Set Multimeter to Resistance 
Isolate Mains Power to appliance as per TOPs P4
Disconnect wires from APS noting their location
Removing APS from appliance may make test easier to carry out
Disconnect wires from APS noting their location
Removing APS from appliance may make test easier to carry out
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, disconnect the -ve connection.
Ensure the performance tester reads 0mb.
Increase the pressure via the syringe to that
indicated on the pressure switch. Continuity
should then be measured across the common (C)
and normally open (NO) connections at the APS.
Notes:
100Pa (Pascals) = 1millibar
If continuity is not measured per test kit instructions
it is permissible to increase the pressure by up to 50%
If continuity is measured keep air pressure switch
charge kit connected to air pressure switch.
Connect the air pressure switch charge kit to +ve connection
on the air pressure switch, disconnect the -ve connection.
Ensure the performance tester reads 0mb.
Increase the pressure via the syringe to that
indicated on the pressure switch. Continuity
should then be measured across the common (C)
and normally open (NO) connections at the APS.
Notes:
100Pa (Pascals) = 1millibar
If continuity is not measured per test kit instructions
it is permissible to increase the pressure by up to 50%
If continuity is measured keep air pressure switch
charge kit connected to air pressure switch.
Isolate as per TOPs P4
and refit as necessary