Water in expansion tank

[karyn2121]

Can anyone tell me what happens to the water in the expansion tank of a boiler if air is added without draining the water first?

Thanks

 

[HERTS P&D]

How do YOU add the air?

Andy

 

[JohnD]

and, indeed, why?

 

[Charnwood]

How do YOU add the air?

Blow in the overflow pipe?

 

[karyn2121]

Well I had my boiler serviced and they said they used a foot pump to add air back into the expansion tank and then I discover a whole load of water under the floorboards. It is definitely not a leak as no other water has come out in s week. They said they drained the water first then added the air but I am not convinced of this

 

[JohnD]

It sounds like you have quite a modern boiler with no expension tank. Instead it is pressurised, and there will be a pressure gauge on the boiler, perhaps reading 1 bar or something.

There is a sort of air balloon inside the boiler or nearby in a metal container, which accomodates changes in pressure due to the water heating up, by getting partially squashed. Sometimes this has to be pumped up.

If you have found water under the floor and they said they had drained it, then perhaps the took the shoddy shortcut of letting water out under the floorboards instead of attaching a hose and running it to a drain.

It might help if you explained what was being done, and why - were you having a fault repaired?

 

[karyn2121]

It was a noise in my boiler that they were out to fix. The boiler is not new as it is 17 years old and is not a combi boiler

 

[JohnD]

does it have a pressure gauge?

 

[karyn2121]

I don't think it has one, it is a valliant thermocompact 142 boiler if that is of any help

 

[JohnD]

the 142 can be a pressurised boiler with an expansion vessel. Have a look for the pressure gauge, it may be behind a flap on the front.

How did you find this water under the floor? how long has it been there?

did you see them pumping air in? did they charge for it? have you got a written bill? what do you know about the qualifications and reputation of these people?

 

[karyn2121]

The guy came out on the Tuesday and leak noted on the Friday. The boiler is in a cupboard above the stairs landing and water then dripped through the ceiling. I did not see him with a pump or any tools but I was in and out the room. It was British gas I called out under a home care agreement due to the noise from the boiler. Unfortunately the boiler did not make the noise while he was there so he said he just topped up the pressure and to call back if noise continued. It was not until another engineer came out that I was told that on the notes on the system said he had added air. British gas denying all responsibility for water damage and originally told me I had a leak in the cold water pipe and made me lift floorboards in cupboard where boiler was! There is definitely no leak in the water pipe as no water since! It was even suggested by them that maybe rain came in along the horizontal flue! Nearly 1 litre of water.

 

[karyn2121]

I uploaded some pictures but I don't know where they went. If you are able to find them the first one shows my stairs and on the right hand side you see into the bedroom where there is a cupboard door open. This is where the boiler is. The ceiling at the bottom of the stairs is where the water came through. I also uploaded a picture of the pipes leading into the boiler where they said there was a leak on the cold water pipe (which they could not find as there is no leak). The water was sitting under these floorboards and there was no sign of it from the cupboard.

Thanks for the help it is much appreciated.

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