Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Turn Hot Water Tap On
Attach a tube from the + port on the telegan to the fan pressure test point
Attach a tube from the - port on the telegan to the gas valve test point
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Allow the fan to run and the ignition sequence to commence.
During the ignition phase the fan pressure should reach
approximately 4mb then drop to 0mb as the gas valve opens.
Note:
When pressure gauge is removed the pressure test point should be tightened and checked for gas tightness.