Hot Water Tank Overflow Pipe Dripping

[Savo]

Hello,

I have a problem with a leak from one of the overflow pipes at the back of my house. I believe it is coming from the electric hot water tank in the airing cupboard and am not sure what could be causing it.

I have turned off the isolation valve to stop cold water coming into the tank and also switched off the heater and left it overnight, but it was still leaking the following morning so I am not sure why it is still leaking.

I can take pics of the tank if that would help anyone identify the problem?

Thanks for reading this post - any replies would be much appreciated!

Thanks,

Ian

 

[tincup]

Hi
You need observe the overflowing tank and report what you see, or not.
For instance which tank is overflowing.
Is the ballvalve dripping

 

[Savo]

Hi tincup,

Thanks for the response. The only overflow pipe I can see coming out of the tank is coming from the top tank. I have removed the lid of the tank and there doesn't seem to be any dripping into the tank from the ball valve.

The overflow pipe is slightly above the water level, although, it comes into the tank and has an elbow joint so that the pipe enters the water vertically and the bottom of this pipe is below the water level - should that be the case? I'm not sure if I have explained that very well so if you would like me to take a picture and attach it to the post I can do this if it would help you to find the fault.

Thanks again for getting back to me. Any further advice would be much appreciated.

Ian

 

[Savo]

Hi,

I posted this thread last week but over the weekend I have found that the isolation valve in the cold water pipe leading to the tank is actually faulty (I turned it off and tried to empty the tank but the water still kept going in). The float valve also does appear to be leaking intermittently so I guess that replacing the float valve may fix the problem.

I have looked around on the forum and it seems like replacing the valve is fairly straight forward, but I just wanted to check if there is anything I need to do when replacing the it. Is it just a case of unscrewing the old one and screwing the new one on or do I need to do anything else?

Finally, the arm of the float valve in the tank seems a lot longer than the arm on the ones at B&Q. Does the length of the arm matter or will the shorter one be ok?

If anyone could shed any light on the above questions I'd be very grateful as I'd like to try to fix the problem as soon as possible as the overflow is starting to leak more heavily now.

Thanks again

Ian

 

[JohnD]

photos will help

I have the impression that you have a hot-water cylinder with a round cold-water tank on top of it.

Have you got a loft as well?

is your boiler pressurised with a pressure gauge?

 

[Savo]

Hi,

Thanks for the fast response. I will post photos later today as my camera is at home at the moment with the pictures on it.

You are correct that I have an electric hot water tank with a smaller cold water tank on top of it. There is nothing in the loft at all. The cold water feeds directly into the small top tank, and there are no other pipes attached to the boiler apart from the hot water out pipe and the overflow pipe.

I can not see any pressurised gauge on the hot water tank and that is the only hot water tank in the house (we do not have central heating so there is not gas boiler or anything like that).

I hope the above information is useful but if I have misunderstood what you are asking then please let me know.

Best regards,

Ian

 

[JohnD]

it sounds very likely that the ballcock needs replacing (it is possible to repair the working parts at negligible cost, but this takes longer)

I would suggest that you buy a brass ballcock as your replacement rather than a plastic one, it will cost a few pounds more. Pegler is a very good brand. You need a "part 2" valve which has a plastic bridge on the top to spray water downwards while reducing the risk of contaminating the drinking water supply

If it is identical, or very similar, you your old one, you may be able to leave the stem in place at the side of the tank, undo the large nut, and fit the working part from your new valve to it.

Before you fit it, examine it so you can see how it screws together, and how you adjust the float height to suit the water level you need.

Buy a repair kit at the same time, and you can fit a new washer and cone to your old one ready for when it wears out again. You can do the repair in your own time with plenty of light, which is far easier than trying to do it inside a dark tank when standing on a ladder. I keep a spare valve wrapped up next to the tank.

You will need some adjustable spanners (wrenches), if you have not already got them you can buy a set of three. Something cheap like Draper Budget will do and might cost about £10

You will also need some kind of torch or lantern as it will probably be cramped and dark. Avoid candles or flames, and if you use an electric extension lamp, arrange it so that no part of the lamp or cable can fall into the water, even if you drop or knock it. This is very dangerous.

You mention that the isolation valve does not work. Maybe there is a stopcock or meter in the pavement, or just inside where the gate used to be. You have got to cut off the water supply before you change the valve. See if it is jammed, maybe it will free if you turn it a fraction one way, then the other, then repeat. If not, you will have to change the isolation valve (stopcock) at the same time. Buy some PTFE tape and put it on the olives of compression joints, after you have cleaned them (kitchen green scourers are good) to prevent leaks - it is better than jointing paste.

 

[Savo]

Hi John,

Thanks very much for the advice.

I may not have been clear about the isolation valve - the valve in question was just one of the small in-line valves in the pipe that seems to be faulty (the ones where you use a screwdriver to open or close the water supply). In any case, there is a stopcock under the sink in the kitchen which turns off the entire water supply to the house so I can stop the water going into the tank by turning that off I think. I tried it over the weekend and it seemed to work (apart from a strange tapping noise that seemed to come from the pipes after I turned it off).

I will pick up the required parts tonight and give it a go. Just one final question - you mention using PTFE tape on the olives of compression joints. I'm not familiar with the terminology so can I just check what is meant by that. I assume that I should apply PTFE tape to the thread of the pipe on the inside of the tank before attaching the large nut on the working part of the new valve to it?

Thanks again for such a thorough response - it is really helpful.

Best regards,

Ian

 

[JohnD]

in most cases. it is not the thread that seals the water.

In a compression joint (like how your ballofix is fixed to the pipe) there is a brass or copper olive slid onto the pipe, that fits into a seating in the socket of the valve, and the seal is olive-to-seat. The PTFE tape imptoves this seal by absorbing any irregularity.

In your ball-cock, the seal is a couple of flat surfaces with a rubber washer squashed betwen them, even though a screw thread and nut is used to hold the parts together.

a screw thread will benefit from PTFE only where it is part of the seal, for example radiator tails. It can also be put round the spindle of a tap if it has a gland.

however it also stops parts from seizing together, or being locked with limescale, so is useful on the thread of tap headwork

 

[Savo]

Hi John,

Just a quick message to say thanks for all your help. I picked up a part 2 float valve last night and managed to fix the problem. I did as you said and left the existing stem attached to the side of the tank and just attached the working part from the new valve to it and it worked just fine. The overflow pipe is no longer leaking and the tank stops filling at a much lower level than it was at before so (touch wood) it all seems to be working.

Thanks again for the detailed advice which made the repair very easy to carry out (the replacement probably took less than 10 minutes!).

Thanks again!

Ian

 

[JohnD]

We love a happy ending!

You can adjust the float so that the water is a couple of inches below the overflow pipe, this gives you good capacity and reduces risk of running low when you have a bath.