expansion tank filling up!

[solution33]

We have recently had a condensing boiler fitted with TRV on every radiator now find expansion tank is constantly filling up.

Any ideas on what the problem could be ?

Many Thanks

 

[gas112]

do you have pipes under a concrete or suspended floor downstairs .???
Leaking

 

[solution33]

Hi Gas112

Under Concrete

 

[45yearsagasman]

Shut the system off and turn off the supply to the expansion/header tank and check water level after say 1 hour. If its dropped then you have a leak. Call your installer back to help you.

 

[SimonH2]

Surely a system leak shouldn't make the F&E tank fill. To do that, there is water being added to the system. There are only two places that could happen and that means a leak in the DHW heat exchanger (combi) or primary coil (hot water cylinder); or a leaking ballcock in the F&E tank.

Depending on the system layout, it could be that the TRVs affect the flow, and hence system pressures, such that what was an un-noticable pin-hole in the HWC coil is now able to draw in a little water and back fill the F&E tank.

 

[swbjackson]

I think you're getting confused between an F&E tank and a cold water storage cistern.

 

[SimonH2]

I think you're getting confused between an F&E tank and a cold water storage cistern.

Not at all.
If the F&E tank is filling up, then water is being added to the system - or there's a lot of air getting in and slowly emptying the rads. There are (normally) only the points I mentioned where there's the opportunity to add water to the heating circuit.

A leak in the system would cause the F&E tank level to drop - until the ball valve topped it up.

 

[JohnD]

you have a new boiler and it has an F&E?

What make and model is the boiler? Does it have a pressure gauge?

Is the F&E filling with cold water through the ball valve, or with warm water?

Is it overflowing?

What do you know about the qualifications and experience of the person who fitted the new boiler? Have you called him back yet?

 

[45yearsagasman]

expansion tank is constantly filling up.

I take that to be the tank filling up through the ball valve and not filling up through a split coil. It needs clarifying.

 

[gas112]

JohnD what do you find strange that a new boiler has a feed and expansion tank ??

 

[JohnD]

not so much strange as unusual. Checking.

mine has too.

 

[gas112]

Absolutely nothing unusual about it loads of new boilers are open vented , you need to do more googling

 

[SimonH2]

I think you're getting confused between an F&E tank and a cold water storage cistern.

Not at all.
If the F&E tank is filling up, ...

Just twigged - were you asking if the OP was confused. Ie, is it the header tank filling up (faulty mixer tap) ?

 

[JohnD]

well he hasn't been back since Saturday morning so perhaps we will never know.

 

[solution33]

Hi guys

Thanks for all your comments

initially the system was leaking hot water through the flow pipe into the expansion tank.

Ball valve has been replaced tank still drawing in water.

we don't have mixer taps.

My only theory is that its the tvrs or the cylinder coil , flow pipe??

Flow pipe be situated in wrong position?? Thats where watercoming from intitially we turned down theromstats on hot water cylinder and boiler which stopped flow of water from the flow pipe.