Biasi 24s boiler howling

[JBseymour]

Hi, not sure where to start process of diagnosis... Boiler is howling when started up. When I adjust the CH heat control dial (LH knob in photo) on front of the boiler for less heat it goes away.
If I throttle back gas flow via isolator tap it goes away (gives less heat also)
Not sure if its a water or gas flow valve.
HW demand also makes howling noise.
When boiler has warmed up the noise disappears.
Any ideas greatfully received.

 

[Agile]

Have you checked the gas settings?

This will happen if overxxxxxx and disappear when modulated back.

Will also be encouraged if some lime scale in the main HE to.

Tony


EDIT had to redact a word above as I realised I had inadvertently given some gas advice which we cannot do here.

 

[JBseymour]

Thanks for reply...Is checking the gas settings a DIYJob? Is it also possible to descale the HE?

 

[32 Heating]

I agree with Agile regarding gas pressures. A gas safe engineer will check both working and operating pressures for you. I also advise not altering the gas isolation valve but I'm pretty sure you only did that to test it? Sometimes air restrictions in the combustion chamber can cause howling as its gets hotter and colder in the chamber it alters the air pressures. Just check your flue terminal is clear outside too

 

[Agile]

Neither really.

Although you could measure the maximum power input at the gas meter from info in the FAQ on this site.

Even so would need careful interpretation from the manufacture's specifications.

That should also be checked at the annual service whit it seems you don have done.

Tony

 

[JBseymour]

Haha...yes sorry just adjusted the ISO valve for diagnosis purposes and opened up fully after. Regarding the servicing we've just moved into a new(old) house.
Dont have any history with Boiler but the elderly lady wont have serviced it herself.
I've never heard of Biasi before this (seems the cheapest Boiler available through screwfix)
Not sure whether to put money into new boiler...

 

[32 Heating]

Yea they aren't the best really in my opinion but are easy enough to work on and service.

 

[JBseymour]

So best thing is to get an engineer as its not likely to be water flow related?
Looking at the FAQs I'm probably breaking the law taking the front cover off to look inside