Set Appliance State:
Gas Off
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Turn Hot Water Tap On
Boiler ON/OFF switch OFF
Remove green wires from air pressure switch terminals marked 1 & 3 and make safe
Attach multimeter leads to spade terminals marked 1 & 3 on air pressure switch
Remove green wires from air pressure switch terminals marked 1 & 3 and make safe
Attach multimeter leads to spade terminals marked 1 & 3 on air pressure switch
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Boiler ON/OFF switch ON.
Allow fan to run.
Is there short circuit resistance as the fan runs?
Note:
Red tube connects to P1 to the back of the air pressure switch,
and the clear tube connects to P2 towards the front of the switch.
Allow fan to run.
Is there short circuit resistance as the fan runs?
Note:
Red tube connects to P1 to the back of the air pressure switch,
and the clear tube connects to P2 towards the front of the switch.
Isolate as per TOPs P4
and refit as necessary