heatslave 12 14 lockout

[bagel]

Can you point me in the right direction to resolve an ongoing lockout issue please?

Worcester Heatslave 12/14 oil boiler with Electro Oil Inter B9A burner.

Lockout is occurring after about 3 to 4 minutes. It is the same if water only or water and heating are called for. I have checked the oil filter - ok - and cleaned the flame sensor. Nozzle was changed six months ago.

Sequence is;

Reset lockout
8 seconds to flame.
Click of relay? after 3 to 4 minutes.
About 20 seconds to lockout light
About 45 seconds to fan stopping
About 10 seconds to click of safety device.

This happens time and time again.

Any ideas please?

 

[leakydave]

Oil Solenoid?

 

[dcawkwell]

If flame is establishing.
Most likely causes are solenoid and or solenoid valve.