DIY Doctor UK DIY Forums

We keep our hoover in the airing cupboard and when my mrs pulled it out she knocked the 'red tap thing' to the right hand side of the cylinder which sits on a pipe entering the bottom right of the cylinder.

Unfortunately turning it hasnt completely stopped the leak and we get a drip every 5 minutes or so. For now I have just put a bowl under there and am presuming that the valve is going to need replacing as it is dripping from the nut under the red tap.

What is this tap actually for? - I presume it is to shut off the cold feed into the bottom of the cylinder? but anyway it drips!

Second question is unreated ans sounds a bit stupid. I am changing my taps in the kitchen and have turned the stop cock off which works fine and cuts off the cold water. But how do I turn the hot water off!! Sounds stupid but I havent done it before and I presume the hot water just comes from the cylinder...... surely I dont need to leave the taps on til it has run empty?

That "red tap" gate valve - will close the hot water off, but they are prone to sheering off so don't overtighten.

Best thing to do is, turn off cold water, turn off heating and run the hot tap - it will stop running eventually then the tank has drained. As the cold water is off - the tank cant refill.

You could undo the nut behind the red wheel, loosely wrap some ptfe tape around the spindle then tighten it up. This should stop the leak. But best bet would be to fit new valve.

so when the cold supply is off and the hot water has finally drained via the taps, there will be no water in that pipe with the valve?

I was under the impression that the hot water would come out of the cylinder at the top next to the immersion and wasnt really sure what that section did. Wont the cylinder refill from the header tank - thus having to drain through all that water as well (which will eventually empty and not refill as the cold feed is off)?

How does that valve stop the hot water from the cylinder if the hot water exits the cylinder at the top? Is the pipe in question the return from the boiler into the coil?

I just need a bit of clarifying how these things work!!

So to go back to my first post and the kitchen tap replacement question - if that red valve tap wasnt knackered, this would have been how to turn the hot water off? Its just funny that the red tap was in the open position and by having it knocked towards the closed position (very slightly) by the hoover, it has caused it to leak. If anything I would have thought it would have shut it off?

The red gate valve is normally where you would turn off the hot water, knocking it with a hoover would not turn it off - as it takes 7 or 8 revolutions to close the valve.

There shouldn't be any valves on the flow and return pipes ( where it connects to the heating coil). If someone has fitted one here then i've no idea why. If the valve is on the return pipe then you will have to drain the system from near the boiler - to change the valve (fit a connector, not a valve).

If there's no valve to turn off the hot water, then turn off the cold water and run the hot tap till it stops. You can then renew your taps.

Yes the cold water tank that supplies the cylinder would also drain, but would refill when the water is turned back on. Why would that be a problem ?

Look in the project section of this forum to identify the pipes.

thanks for your help..... Im just trying to get my head around it thats all as its all new to me (hence lots of questions) but you have to have a go and learn sometime!

All I meant with the red tap is that its on a pipe that goes into the bottom of the right side of the cylinder and I just thought the hot feed to the taps comes from the top of the tank (no shut off there). At present the tap is fully turned in one direction and the knock of the hoover maybe turned it half a turn or so in the other direction. When I went to return it back to where it began I mistakenly turned it in the other direction and the drips got worse, I then realised the correct direction and turned it back but it still drips abit. The tap seems like theres a lot of play in it - but as you say, to turn it off would take a fair few turns..... it just concerns me that if I carried on turning it the drips would change to a gush as its this direction that seems to cause the leak!! Do you think if I just carried on turning it would eventually cut the water off likes its supposed to? just feels very loose like the actual tap handle was just unscrewing.

The only problem with draining the header tank as well was the waste of water and the time it would take!!

Thank you for your help, its been of much use :)

Your hot water cylinder has 4 pipes leading into it? If we call the one at the top pipe 1, the next one down pipe 2, the the on nearest the floor is pipe 4?

If the valve is in either pipe 2 or 3, then it is part of the heating circuit and adjusting it will cause problems.

If the valve is in pipe 4, this will shut off the water to the cylinder and hence stop it coming out of the top and the hot taps will run dry after a few seconds.

Just behind the red wheel of the valve is a small (1/2" or so) nut which is a gland to stop water leaking. Try tightening this nut up a little (1/4 - 1/2 turn).

There's a slight communications disconnect here.

The hot water only comes out of the top of the tank because of the pressure difference between the cold tank in the roof space and the HW cylinder.

Nitro you are is correct in that the pipe with the valve concerned on it does bring cold down to replace hot when a tap is opened. Htg engineer is also correct because based on how I've described it if you shut off that valve the cold can't come down any more so the hot won't come out and shutting that valve does shut off the hot water. Does that make sense Nitro?

If you are worried about wasting water if you go up in your roof you should (but may not) find a number of additional valves up there. One to cut off water supply from mains to the tank and another to cut off supply from the tank to the rest of the system. If you shut the latter (assuming there is one) then there is no need to drain the CW storage tank. If there isn't the tank will have to be drained.

Anyhow to the immediate problem. On the valve spindle there is a nut which has been identified I believe and this is where the leak is occuring - probably because its come undone a little. Try tightening it up using a spanner but not too much because, as htg engineer has pointed out, they can be a bit fragile. You should close off the leak by being careful. In the long term the right solution will be to change the valve.

Cheers

Don't know why I said Othello in last post. Brain fade clearly. I meant Nitro - sorry.

Now it's been passed through I've edited it.

Cheers

Cheers roseberry,

I finally managed to figure out what you said - could have done with that yesterday!! :)

Mysteriously the slow drip has stopped itself now (maybe some salt or something). My only confusion now is with the cylinder as it has five pipes in/out of it.

1.The top hot supply out with vent up to the roof space
2.The boiler flow
3.And return
4.A feed in from the roof space (not the pipe with the gate valve ??) that goes in the bottom left which also has a drain cock on it.
5.A pipe with the gate valve into the bottom right - this doesnt appear to come from above but joins up at the front to another pipe.

A couple of these pipes join at the front where the pump and motorised valve are.

Most systems seem to have four pipes, so Im still a little bit lost!!!

UPDATE:

Got home from work and thought sod it and decided to turn the gate valve to the closed position..... after about 8 turns it finished turning (I presume full circle). The drip did return from under the nut but the water coming out was actually blackened.

I turned the bathroom hot water tap on but it still came out, I turned it back off after about 30 seconds - how long should it take to stop if it had worked?

I then returned the gate valve to the open position and it did sound like water was re-entering the bottom of the tank..... so I wonder if I just didnt leave the hot tap on long enough?

I realise all this sounds stupid to the knowledgeable, but I am a bit tentatent in case I break something!

ALSO the gate valve in question the pipes are warm to touch when the heating is on. The only one that is cold is the pipe that goes into the bottom left (number 4 from my post above).

Time for a pic methinks if at all possible.

Cheers

Right heres some pics!!

While your here tell me whats what including what I think is the pump (settings 1,2,3 currently on 2) and the motorised valve (whats this? settings H M and W - what are these?)

Also you will see there are 5 pipes in/out with one in the bottom left which I feel is prbably the header tank cold in and bottom right with the gate valve (which gets warm to touch) - it is these two I am confused about.

It is an indirect cylinder and I have been up to the loft and I have the header tank and expansion tanl, both of which are working normally as far as I can tell.

http://img141.imageshack.us/img141/9092/62201759um6.jpg

http://img147.imageshack.us/img147/7213/63552354ev1.jpg

http://img181.imageshack.us/img181/705/43881423hm9.jpg

http://img181.imageshack.us/img181/4048/51617402fs8.jpg

http://img181.imageshack.us/img181/4048/51617402fs8.jpg

The pipe shown in

http://img147.imageshack.us/img147/7213/63552354ev1.jpg

is probably a Surrey connection to a mixer shower.


The red gate valve shown in

http://img181.imageshack.us/img181/4048/51617402fs8.jpg

is a restrictor valve in the secondary heating system. Closing this will stop the hot water getting hot. Opening it up will stop the radiators getting warm. It is not recommended to adjust this unless the heating is imbalanced. Turning this valve will have not stop the water from the hot tap.

Tighten the nut as I suggested to assist the gland from leaking.

Well I take it all back. I was completely wrong - a picture tells a thousand words after all. For some reason unbeknownst to me you have a gate valve in the primary circuit on the boiler return leg. That's the bottom right pipe. That has nothing to do whatsoever with hotwater supply to the taps from the cylinder nor the cold supply to the cylinder.

Funny though you don't appear to have one on the cold feed down from the CW tank which is the bottom left. So unless you can shut that off per my previous post then it looks suspiciously as if you will have to drain everything in order to change the taps. Of course having drained it all that would be a good time to put some more valves in!

The pump is the red Grundfos device in the centre which BTW is completely inadequately unsupported. You must get noise and vibration from that I would have thought. This is on the flow direct from the boiler.

The grey box on the RHS is a three port mid position diverter valve. When the cylinder stat says you need hot water the valve opens to allow the hot water from the boiler to go to the upper pipe on the RHS which is the top of the coil within the cylinder. W position. The bottom of the coil is the pipe with the gate valve in it and from there the water returns to the boiler to be reheated.

When the central heating is on but there is sufficient hot water the valve moves so that the indicator is in the H position and all the heated water from the boiler is diverted to the radiators.

If both DHW and CH are calling for heat at the same time then the valve settles in the mid position M where the heated water is allowed in both directions at once.

Do you have a separate shower (perhaps with a thermostatic valve) in your bathroom? Although I can't see it exactly I'm assuming that the fifth pipe (LHS halfway up) is connected into the cylinder using an ******* flange so that the shower can operate independently from the taps and operating a tap neither scalds nor freezes the person in the shower. This is very much an assumption though.

Hope this helps

Cheers

HaHaHa - can't even use the proper terminology for an E s s e x flange 'cos the built in censor deletes it.

Cheers