Explosive ignition in boiler

[Gem106]

First post. We have a biasi Rivera HE boiler. The LL has had loads parts replaced on it. Working perfectly until last few weeks especially when the hot water tap was turned on it ignited with boom ( like someone had slammed the door very loudly) some of the plaster had come off the wall as well. Had someone in today who also fixed out leaky radiator in the bathroom as well. He adjusted the pressure. Surprise! The boiler didnt ignite with a boom when CH turned on or HW tap so he couldn't see anything wrong . The flame was a nic blue colour as well. He said to contact him back if it happens again, but nothing he can do. After he left I noticed a dead wasp and a dead ladybug looked like they'd been burned to a crisp so unless that was blocking it as they couldn't have been burned like that anywhere else. Could this have been the issue. Also got someone coming over tonight to have another look as well and see what he thinks so will be mentioning this as well. The other guy said it could have been a bit of dirt. Nothing has actually been cleaned but took it apart had a look and put it back together again

 

[footprints]

Chances are a short pilot, could well be something blocking it that has shifted.

 

[Gasguru]

Pilot...okaaaay

It sounds like it's a Riva of somesorts..there are several versions.
Boiler combustion chambers are often full of crispy wildlife that get drawn in via the flue...it's perfectly normal.
Biasi manuals are amongst the best in the industry and this should be a simple fault to resolve.
Can we assume tonights eng. is a registered gas installer?

 

[footprints]

Pilot...okaaaay


OK cross lighting jet or whatever Talking of wild life in boilers I once found a well cooked mouse in a Neataheat fan, poor little sod must have thought it was a motorised exercise wheel!

 

[Gasguru]

DBI on Biasi boilers.

 

[Gem106]

The second gas engineer did not turn up. Been told that if it happens again to ring the gas engineer back and see what he can do