Hi,my glow worm flexicom 15hx boiler open vent(3yrs old)is causing me problems...it fires up ok,but after 5 mins/2 hrs a bang comes from the boiler..its like a mini explosion..i had someone look at it,but no joy...please could anyone advise me what to do next or what the problem could be...i know nothing about boilers and im a new user on this site so i hope i've posted this ok..many thanks...
