Oil Central Heating Boiler - Lockout Help and information on all topics relating to your central heating, air conditioning and ventilation issues.

[gaudonville]

I have a Lamborghini oil fired central heating boiler which goes into LOCKOUT intermittently. The burner is a Lamborghini 32kW and seems to be of conventional design. At the ignition stage it sometimes goes into lockout and I don't understand why.
I have checked the fuel supply - no problems
I have cleaned out the burner itself, the combustion chamber and the flue (balanced)
I have checked the incoming air supply
It seems as if there is a device within the boiler which checks whether the combustion chamber has been purged properly before allowing ignition but I don't know what this is or where it's situated. I have the handbook but it only shows the electrical circuit diagram in detail.
Can anyone please suggest a solution? (Please don't suggest calling out an engineer as this is a DIY site and I am reasonably capable if I know what I'm looking for)

[plumbbob]

There is a lockout sensor that visibly detects the presence of a flame. If the photocell "glass eye" gets covered with dust or soot, it may not be seeing the flame enough so triggers the lockout.

The sensor pokes into the combustion chamber and the leads connect to the control box.

Only fiddle about with the power off, because if you confuse the wires with the spark electrodes, you could be in for a nasty shock!!!

[gaudonville]

Thanks for your suggestion but I'm sure that it's not that because the problem is intermittent and lockout occurs prior to the signal to pump oil to the jets and therefore it can't be looking for a flame at that stage. Any other ideas very welcome. Regards

[plumbbob]

That's odd, because the lockout timer is triggered by the opening of the oil valve. If the boiler is reaching lockout before ignition then either the PCB is faulty causing an instant lockout regardless of condition or the flame is failing to ignite fast enough allowing the lockout to time out.

A failing lockout circuit will trip often during a normal burn cycle when the flame is well established. The boiler will suddenly and for no reason shut down.

I think you need to confirm that the oil valve is not opening sooner than you think and failing to ignite.