worcester heatslave 20/25 occasional "phaaat" type

[selectcase]

Hi All

I have a worcester heatslave 20/25 oil fired combi boiler that was fitted 6 years ago. We have it serviced every year but reciently it has started to make a kind of Phaaaaat noise with some small vibration for about 2 seconds about 30% of the time when firing/heating the water. When we had it last serviced in may the guy said that it just needed a new nozzle as it wasnt always firing up due to a clogged jet and re-charging which seemed to cure it for a short while?

could it just need a new nozzle/service again as it all works fine in every other respect?

many thanks

will

 

[wilhelm]

could be weak EBI transformer.

Although your description sounds like over firing.

........

 

[oilman]

Nozzle is unlikely to be the problem.

Exactly what happens during startup. This is not a common occurrance, so diagnosis might be difficult

 

[selectcase]

You hear the motor/pump running for a few seconds, then you get this noise for about 1/2 second- then it fires

sorry for the poor description - I had better call out an engineer to have a look

thanks

will