Strange Noise from Back Boiler

[mortosm]

For the first few minutes when my back boiler fires up I can hear an occasional 'sizzling' noise (like the noise a drop of water on a hot coal would make). This only happens for five or so minutes. The boiler is behind our fire place and flues vertically upwards via the chimney. Any ideas?

[milliezoe]

Could be a tiny leak somewhere as the boiler fires up once it is hot there is no sound anymore do you have to vent the system ie radiators if you do then you have a leak on the system a competent heating man will be able to diagnose the problem

[tezestwing]

if you are able to have the back boiler of for a while evidence of water should prove a leak.
some time you may get what they call "kettle ling"this could have several reasons, age, poor circulation, air. unfortunately some of these back boilers do not reach sedbuk efficiency and spares are a problem to. happy new year HTH Tez

[gucciman]

what precisely does the back boilers not reaching sedbuk efficiency have to do with anything??????
as for spares if its a baxi back boiler than spares availability is not a problem at all. and even for other types of back boilers like maxols then a competent time served "real" gasman can adapt parts and keep them running. the beauty about these old style boilers is that they are simple and will far outlast any combi boiler, we regulary see examples that are 40 yrs old or more and still going strong.
mortosm, have the boiler serviced and the engineer can look for any faults at the same time.

[tezestwing]

gucciman I have a good old glow worm galaxy vintage 35 years how do I know what mortosm has I was just trying to relate the probs I have to service mine also future pobs with the dreaded HIPs vis heating and insulation factors that what abers are for isn't it and you ought to know all about SEDBUK if you are corgi registered Tez

[tezestwing]

sorry HIPs relates to energy performance certificate that speaks for itself HTH Tez

[mortosm]

thanks to those who have responded to my question. It turns out there is a hole in the heat exchanger, and water is dripping onto the hot parts causing the 'sizzling' sound. When the system heats up the metal expands, closing the hole. That is why I only hear the noise for the first 5 minutes or so.

[gucciman]

i know what sedbuk is, ive done the incredibly boring energy efficency course. i was referring to what has the sedbuk rating got to do with his problem with the boiler, i'm not interested in hips and im not the sort of person who would try to talk someone into buying a new boiler off me if their old boiler is still going strong and spare parts are available, especially as theyre going to be really annoyed when their lovely new efficient combi breaks down every couple of yrs and dies completely after 10

[gucciman]

did you call an engineer out? did he manage to fix it ok?

[persianlady]

Well said gucciman! Your reply was reassuring to those of us who do have a back boiler.

[mortosm]

British Gas are replacing it next week. It works ok in the meantime as its only the odd drop of water. Apparently the repair will take 4-6 hrs...

[gucciman]

christ almighty, i hope you have a service contract and didn't just call out britsh gas on the offchance, they'll charge you double (at least) what anyone else would!
i bet they tried to talk you into ripping out your back boiler and having a nice shiny new combi off them? well doen for resisting.

[gucciman]

both me and my father have baxi back boilers in our houses, cant beat them, my dads was one he rescued from a skip 10 yrs ago and its still going strong. he always urges anyone who asks us about converting to a combi to stick with their old systems. he was the main combi expert at british gas for many yrs, he makes great money repairing them and yet he hates them, unreliable, overcomplicated and hard to repair.

[mortosm]

yes, fortunately I have a service contract. I have only lived in this house for 8 months and thought it prudent to get BG cover because I had no idea of the boiler history. It turns out the previous owners had never had it serviced, cleaned etc. it amazes me that people are so complacent about the potential risks from a boiler. Especially since the previous owners had 2 very young children and no carbon monoxide detectors. Mind you, they didn't have a single smoke alarm either....

[persianlady]

I thought only Gordon Brown used that word.... Prudent......
You're not are you????? lol

[persianlady]

mortosm...... How much does this service contract cost if you dont mind me asking? I think it is something I should do if I can afford it.

[mortosm]

contract is �25 per month for boiler, central heating, electrics and plumbing/drainage.It costs less for just boiler and central heating. it also varies somewhat on postcode (i'm in the south east). I've been on the contract for 5 years (in my previous house too) and its been worth every penny...