Worcester Danesmoor 20/25 utility. Starts and runs for about 4 minutes (give or take 20 seconds), then goes to lock-out. I have replaced the photcell but no difference. Any ideas, a service is due in about 3 weeks. Worcester want about £300 to come and look at it. I have just lost my job so money is not plentiful, £300 is way too much..

George G, August 2009

it could be the fuel pump solonoid,sometimes there is a fault with them,when they heat up a certain amount something expands and breaks contact untill it cools sufficiently for it to make contact again.It is very easy to replace,connector plug on the end,and i screwed cap

John Buchan, October 2009

Thanks to everyone for their help. Fitted new coil and it works fine and I have saved a load of money. I am a little nervous working with these boilers, I used to design the control systems for large gas-fired industrial systems (100 - 500kW) so everything on these domestic boilers appears a little small and delicate.

Anyway it is now fixed and I know a bit more about how it works.

George G, August 2009

2min Job (for an Industrial Burner man!)

Undo the Brass nut on top of the coil, pull off the moulded electrical plug, get a new coil (about£30) and fit in reverse order, you get a new brass nut in the pack.

www.elanar.co.uk, August 2009

Thanks John and www.elanar.co.uk

Yes it looks like a solenoid problem, ignition is good (about 11 second delay), oil delivery is good, flame sensor has been replaced just in case. I have borrowed a plug-in controller and the same problem occurs.

Do I just unscrew the brass plug holding the solenoid onto the pump to release the solenoid? I am concerned that I may upset some settings as I don't know much about these boilers.

George G, August 2009

The solenoid actually switches the oil supply on within the pump....initially the burner fan will run to purge the boiler with fresh air - after about 8 sec ignition starts, together with the oil switch on. Thats why ignition isn't immediate.

John, August 2009

A good Service about £80 inc filter & Nozzle, Sounds like a new Solenoid coil will be required about £45, so at most should be about £150 to sort

Worcester charge a fixed price fee, which is good if you have a combi with a million leaks and faults, but in this case, you would be the loser

www.elanar.co.uk, August 2009

Thanks John

The combustion sounds good and even, I worked in industrial heating systems for years so I am familiar with combustion, purging, flame sensing etc. Just no experience with small domestic systems. If I let the boiler go to lock-out it will restart after a short period - say 2 minutes.

What does that solenoid do? It doesn't feel warm to the touch when running or after lock-out.

George G, August 2009

Initially George I would think that the solenoid on top of the oil pump could be failing here - if the boiler gets going again once it has cooled off. Mind you, it could just be that the whole boiler needs a good clean out - from firebox, through the baffles to the flue. A good indicator of needing a clean is a chuffing sound when the burner is going, and black smoke at the flue.

John, August 2009