Keston 25 bubbling boiler

[FieryJack]

hi

Have a Keston 25. Has been regularly serviced.
The boiler has started gurgling, with a distinct bubbling sound heard both at the boiler and in the outlet flue.

I mentioned it to the service engineer when the boiler was serviced during the summer, saying that the noise started in early June when the central heating was last used. over the summer when we've used the boiler for hot water only, the noise wasn't there. Now we need the heating back, it's re-appeared. The service engineer suggested bleeding the radiators, which we've done (twice, to be sure).

I've been scouring forums and seen posts about kettling, but I don't think the boiler is running too hot. Am wondering if scale is a problem, but would have thought that might be obvious when the boiler was serviced (in late June).

Can anyone suggest other possible causes, before I embark on what I suspect will be an expensive problem-solving exercise?

thanks.

 

[corgiman]

Blocked Condensate pipe/trap I reckon

not too bad for a service chap to sort

 

[spacethegas]

Blocked Condensate pipe/trap I reckon

not too bad for a service chap to sort

you wont get ignition if trap is blocked.

ive got the mi in front of me just by chance.

the trap does gurgle a little under normal operation & this would probably be more evident under ch operation.

 

[corgiman]

Blocked Condensate pipe/trap I reckon

not too bad for a service chap to sort

you wont get ignition if trap is blocked.

ive got the mi in front of me just by chance.

the trap does gurgle a little under normal operation & this would probably be more evident under ch operation.

I was thinking more of a parital blockage causing a bit of hubble bubble up the primary flue

Seen it a few times, usually because the bleedin thing has never been serviced properly

 

[spacethegas]

certainly possible.

 

[FieryJack]

thanks for the feedback.

so having forked out for one service 3 months ago, are you recommending I get it serviced again?

 

[spacethegas]

it will certainly need the attention of an rgi with appropriate knowledge/experience.

 

[ollski]

Yep the clear plastic tube gets backed up, the things then sound like a washing machine.

 

[ollski]

duplicate

 

[FieryJack]

I called the guy who did the service and he told me how to remove the plastic pipe. Once removed a whole stack of sludge came out.

Boiler and central heating working fine now.

As a matter of course, should the outlet flue be checked as part of a service? And is this build-up of sludge common?

Thanks very much for your help.

 

[spacethegas]

both air intake & flue pipes should be visually inspected as far as is possible on a service.

it is not usual for a 'build up' within 3 months.

during the service i tend to pour plenty of hot water down the heat exchanger so as i can see how the trap operates.