persistent header tank overflow activity

theboygeorge

I have have a gravity fed boiler system, I have 2 tanks in the loft, the smaller central heating tank constantly over flows.

When I investigated this I found the level high and the ball !!!! was sunk, I removed about 3 Ltrs of water ,dropping the level by about 2". The ball !!!! valve did not kick in so I hoped that this would be the end of matters.

Two days later the same problem occurred,

I would be grateful if some one can explain what is happening, and give me a possible solution.

regards
Colin

keystone

Ball full of water possibly combined with duff washer in valve. Ball is easily replaceable - just screws on end of arm - if it has a leak. Washer also easy to change but more often than not its quicker and easier just to change the whole valve because inevitably the valve will be gunged up and not want to come apart very easily. Complete valve and ball for less than a tenner HERE Could do it for less with cheaper valve. About 15 minutes to change it over. You should fit a Part 2 valve with the bent arm as link and not a Part 1 with the straight arm.

Cheers

MickMack

theboygeorge wrote: »

When I investigated this I found the level high and the ball !!!! was sunk, I removed about 3 Ltrs of water ,dropping the level by about 2". The ball !!!! valve did not kick in so I hoped that this would be the end of matters.

So if i interpret this correctly, your tank has been overflowing but you saying that the ballcock is not running constantly?

You said that you removed water and the ball valve didnt kick in, which would suggest that the washer is ok, but it would also suggest that the float is ok too.

have you checked your radiators for air in the system?

Also you could try removing more water from the header tank until the ballcock does kick in, then watch to see how it fill to a cut off

Also were you doing this when the system was hot or cold as that will affect the level in the header tank

theboygeorge

Hi thanks for your replies, is the ball valve the only way of putting water into the header tank or can it draw from the central heating system in some way?

does the central heating system draw from the header tank?

cheers
Colin

alleycat`

You could also be suffering from pumping over into the expansion tank if it happens when the Boiler is on.

Pumping over' is where water is forced up the 'open vent' into the Feed / Expansion tank.

Causes can be;

- The circulator pump is incorrectly sited
- The pump is oversized
- There is a restriction or fault in the system

If it's an old system i'd go for number 3.

This assumes you are 100% sure it isn't just the ball valve letting water through (which is the most common cause).

Or you haven't replaced radiators / drained it down and left a load of air in the pipes.

Mister_G

I had a similar problem which turned out to be the primary coil in the hot water cylinder being perforated. This led to hot water from the secondary side (the stuff that normally comes out of your taps) being forced into the primary side. The result was an overflowing header tank.

I must admit it took me a while to find it, which I did by turning off the cold feed to the header tank. With no water coming into the primary circuit, it could only be coming from the secondary.

The solution was to replace the hot water cylinder. I also drained and refilled the primary circuit with new inhibitor, as the old stuff would certainly have been diluted by the flow of water into the primary circuit.

All been ok since then.

Not sure if this is your problem, but may be worth checking.

G_M

http://www.cfplumbing.co.uk/what-is-a-feed-and-expansion-tank.htm

http://www.diynot.com/forums/viewtopic.php?t=38593

http://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl?num=1105990608

http://www.ultimatehandyman.co.uk/forum1/header-tank-overflowing-not-the-ball-!!!!-t31745.html

http://www.handymanknowhow.co.uk/plumbing/cisternoverflowing.htm

southcoastrgi

wow someone has alot of time on their hands

southcoastrgi

if the ballvalve isn't running & the water is low enough (should be about an inch above the cold feed at the bottom) then i'd tend to agree with post #6

G_M

southcoastrgi wrote: »

wow someone has alot of time on their hands

Hey - super fast broadband and google. 2 minutes to find 5 links!

keystone