Set Appliance State:

Mains Power Off
Ensure No demand for CH or DHW
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

The green power LED should illuminate and boiler should enter standby, pump should not run and boiler should not attempt to fire.
Does the LED illuminate and boiler enter standby?
Note:
For fault LED lockouts that do not appear during this test choose
"boiler enters standby" and select fault code on the next page.