Dripping Overflow Pipe

bruceyboy · 17 Apr 2007

I hope someone can help. My knowledge of central heating systems is limited so please bear with me.

I have a boiler in the bathroom with a hot water tank and then have two tanks (one big and one small) in the loft. We haven't been in the House that long but the system cannot be more than four years old as I know the previous owner (a plumber) completely overhauled it.

The overflow from the tanks seems to leak constantly. It isn't just a small drip but a constant trickle. I'm not sure whether the source of the water is from the small or large tank but the trickle stops when I run the hot water for a couple of minutes only to return a few hours later.

Any idea as to what this might be and how i might solve it? Any help gratefully received.

Many thanks in advance.

Fluffster · 17 Apr 2007

Sounds like your cold water storage tank float valve may not be closing off fully.
Have a look at the larger tank in the loft and see if water is dripping from the valve.
If so it is an easy fix either replace or repair they are v cheap part.
If water is coming from the vent pipe over it (shaped like swan neck) a different story.
Pete

bruceyboy · 17 Apr 2007

Thanks. I'll take a closer look this evening. Would I need to replace the whole part or just a washer (I remember having a similar problem with a toilet a couple of years back and just replaced a washer).

If that is the problem. Presumably it's a case of turning off supply to the tank, draining water down, replacing the part and then refilling the tank?

Fluffster · 17 Apr 2007

No need to drain the tank just shut the water off and replace the valve, they are about £5 you need a brass one.
P

bruceyboy · 17 Apr 2007

That's great thanks. I'll come back to the forum tomorrow if I get stuck.

Most grateful for the speedy response.

Softus · 17 Apr 2007

Before you do that, check that water is coming from the float valve.

If not, feel the temperature of the water. If the cistern is lagged and has a lid, then the water should feel extremely cold.

If it's at all warm, and there's no water coming from the float valve, then you have a faulty mixer tap being fed from unbalanced supplies.

bruceyboy · 17 Apr 2007

Thanks. Sorry to appear a bit clueless on this but should i be checking the temperature in the bigger tank in the loft? Surely if the tank is full there will be (or at least should be) no water coming from the float valve?

If there is any warmth in the water, denoting a problem with the mixer tap and unbalanced supplies, I'm presuming that's a big job for a pro rather than a basic diy-er like myself?

Softus · 17 Apr 2007

bruceyboy said:
Thanks. Sorry to appear a bit clueless on this but should i be checking the temperature in the bigger tank in the loft?

Yes.

Surely if the tank is full there will be (or at least should be) no water coming from the float valve?

If the valve is operating correctly, then yes. If you have a faulty or sufficiently worn valve, or grit under the seat, then it won't shut off. This is why it's the first thing to check.

If there is any warmth in the water, denoting a problem with the mixer tap and unbalanced supplies, I'm presuming that's a big job for a pro rather than a basic diy-er like myself?

Don't be so negative!

The first step would be to confirm the theory. If you shut off the mains supply to the entire house, and water stops overflowing from the cistern, AND the valve wasn't faulty, then it's an unbalanced supply to a mixer.

You then need to identify which mixer - determine which of them have a cold mains supply. It's usually a shower valve.

When you've go this far then come back for more information.

bruceyboy · 17 Apr 2007

Thanks. I'll be back in the forum when I've checked it all out - either very grateful for the advice or pleading for more help!

bruceyboy · 17 Apr 2007

Had a look in the tank and it looked as though the ball cock was slightly out of position so i loosened the nut repositioned it and tightened it and so far so good!

Thanks for the advice and I certainly come back should I need more help!

bruceyboy · 11 May 2007

Having originally thought I'd solved the problem, it now looks as though I'm going to have to replace the part and I'd like advice on one of two options which i think I have.

1) the simpler option as far as i can see would be to be to replace the ball float with a bigger one (it is quite small at the moment) so that the valve shuts with the water at a lower level and/or there's more buoyancy to shut the valve. This may work but i'm not certain. If this is a viable option, do bigger floats generally have the same size thread as smaller ones?

2) Alternatively I could replace the arm altogether. The problem with this is that I've looked in the shops and the ones on sale don't seem to match the one I have. All the ones in the shops are straight where as mine has a definite kink. Also if I get a new arm do I get one described as Part1 (generally completely straight) or Part2 (straight with an elbow on the end the float attaches to). Is there any difference between the two? Presumably they come in a standard size?

Any tips/advice/guidance very gratefully received!

Many thanks,

Bruce

JohnD · 11 May 2007

You should use a Part 2 (or higher) valve. This has protection against dirty water contaminating the water in the pipe. To fit it you will need two adjustable spanners. Look at the assembly of the new valve so you understand how the old one is fixed. They are almost certainly all half-inch valves (larger ones are available but uncommon). Buy a spare washer set while you are about it.

If it is a brass arm you can adjust the shut-off level by bending it.

Turn off the water supply first, else water will gush out.

To avoid straining the valve, remove the arm from the valve. To do this, pull out and straighten the brass split-pin (or other fastening) on which it pivots. Then bend the arm over your knee. You want to bend it down so that it shuts off the water at a lower level.

If the valve is dripping, take it off and fit a new one. This is easier and quicker than mending the old one.

You can subsequently clean, de-scale and re-washer the old one and put it back in the loft, in a polythene bag tied to the supply pipe at the existing valve, ready for next time you need to change the valve. You can re-use the existing plastic ball unless it has been punctured.

bruceyboy · 11 May 2007

Thanks. Is it acceptable to just replace the arm and valve that unscrews from the side of the tank rather than replace everything including the connector to the supply? I am confident enough to replace the arm but not necessarily the connector too.

JohnD · 11 May 2007

then entire valve fastens to a tap connector, which you don't remove.

I expect you can see a 15mm copper pipe with a brass nut on it. This brass nut connects the supply pipe to the valve. You undo that, remove the old valve (by undoing the brass retaining nut on the threaded tail); clean the hole in the tank, and clean the tap connector, poke the tail of the new valve through the hole and do up its retaining nut; put the pipe onto the valve tail, do up the nut.

Old men like me would use jointing compound on the tap connector, younger folk might use PTFE tape.

Entire valve:

Tap connector on end of supply pipe (the nut fastens to the threaded tail of the valve)

Fluffster · 11 May 2007

"Old men like me would use jointimng compound on the tap connector, younger folk might use PTFE tape. "

I must be middle aged as I use a fibre washer

Pete

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Dripping Overflow Pipe

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