Set Appliance State:

Gas Off
Isolate Mains Power to appliance as per TOPs P4
Turn Hot Water Tap On
Attach pressure gauge to the inlet pressure test point
Gas On
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Cancel purge cycle.
Allow burner to ignite and establish.
Does the pressure gauge show an acceptable minimum
gas inlet pressure throughout its operation?
Note.
When the test is complete the pressure test point should be tightened and checked for gas soundness.