Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
CH Demand
Gas valve base settings
  • Throttle - Screw all the way in then 7-8 turns back out
  • Offset - Screw all the way in then 2 1/2 turns back out
    This is the factory setting and should ensure that the gas/air mix is within normal combustion parameters
  • WARNING! - Mains voltage is expected during test follow
    TOPs P4 live testing procedure
    Mains Power On

    Observation:

    With the gas valve reset to its factory setting does the burner now ignite and establish?
    Note:
    The combustion ratio max/min will need to be checked and adjusted following any procedure that affects combustion. If this is not possible then the boiler shall be isolated from the gas supply until such time that it can be confirmed as correct.