Flushing sound occuring when boiler switches off

[mdeakin]

Hi

I know this sounds odd but when the boiler (central heating) goes off, about 10 minutes after I hear what sounds like a flushing sound come from the back of the house (somewhere near where the boiler is).

I sounds like a bucket of water is being poured out a window ... a strange sound indeed.

By a process of elimination I have figured out its linked to the boiler switching off and occurs around 9/10 minutes after.

Any ideas what this might be?

 

[fullyuntrainedplumber]

I had a flushing sound in my boiler which turned out to be a frozen condensate pipe. OK once I defrosted it.

 

[mdeakin]

Thanks. Someone else suggested it might be air escaping into the 'header tank'

Excuse my ignorance but how do I know where/what my condensate pipe is?

 

[twgas]

What boiler and system do you have

 

[mdeakin]

Hi

Its a Baxi Solo 2 50 PF.

I checked to see if there was anything coming out of the overflow outside but nothing there when the sound was heard.

Mark

 

[mdeakin]

Re condensate pipe, I looked into this online and it appears to be a pipe from the back of the boiler to the outside. I checked and I can see such a pipe coming out of the back of the boiler and outside.

Mark

 

[seco services]

don't surpose you will as its not a condensing boiler

 

[mdeakin]

That'll be why then

When I looked in the loft I have three tanks. One without 'ballcock' and two with. The big one (where the water comes in and has a 'ballcock') has a pipe that feeds into top of it (its u shapes so its not an overflow for the tank .... more that you would except water to come out of it into the tank at some point. that pipe feeds into the very top of the hot water tank.

My feeling is the sound that I hear is water coming out of there into the big tank in the loft but yet to prove that. Spent an hour in the loft with a torch looking a three tanks of water and the sounds didnt happen .... grrr

Will try again tomorrow.

 

[seco services]

if thats the biggest tank then that the supply for the hw cylinder and the pipe is the vent for the cylinder.

the heating system tank will be the small one with a vent pipe aswell.

is the water cold in all these tanks ?