More plumbing problems

  Legolas 19:02 08 Jan 2008

On the back of the thread by acceptmyname I also have a central heating / plumbing question.

The other day the pressure in the central heating system was low this causes a red light to come on on the control panel of the boiler.

Next to the boiler is a valve that lets water into the system to increase the pressure and once done the light goes out and the boiler fires up.

I did this successfully and thought all was well then I noticed that the valve had sprung a leak from the coupling, it is really no more than a slight sweat and I don't want to have to drain the system for such a small leak.

So does anyone know a way of fixing this slight leak without the rigmarole of turning of the water and draining the system?

  anskyber 19:07 08 Jan 2008

If it's a flexible coupling into the boiler it usually has a screw fit which is hand tight.

I understand that it should normally be disconnected after charging the system anyway. (if it's the coupling I am thinking of)

  Legolas 19:23 08 Jan 2008

The coupling and valve in question are not directly into the boiler, the valve as far as I can see is on the cold water pipe and a flexible but permanently connected pipe goes from that onto a coupling in the central heating system piping for the purpose of topping up the system I assume. It is the valve on the cold water pipe that has the slight leak.

  Forum Editor 19:24 08 Jan 2008

One end is connected to the mains water supply, and the other to the boiler's central heating circuit, via a one way valve - water can pass from the mains to the heating circuit when both the mains valve and the one-way filling valve are both open.

In modern combi boilers the filling loop is an integral part of the boiler - you have two valves built in, which are accessible (usually) on the iunderside of the casing - but in older models the flexible loop had to be fitted by the installer, and originally there was a rule that the connection to the valve at the boiler end should only be made when the system needed topping up - it shouldn't be left permanently connected.

That's why - as anskyber said - the connection is usually a hand-tight one; you can simply tighten it a little more if it weeps. This type of connection has a neoprene rubber washer that makes a watertight seal, and unless the washer has perished it should tighten and remake the seal quite easily.

  anskyber 19:27 08 Jan 2008

If it is like a tap?

Then the leak is often from the gland area and a slight tightening of the nut seen at the point where the tap shank disappears into the body usually does it. If not that design then sorry!

  Forum Editor 19:27 08 Jan 2008

that has the leak.

In which case it's a compression joint, and can be tightened with spanners at the copper pipe side - two spanners are necessary. If it's a Balofix valve (one which operates via a small slot that you turn with a screwdriver) it might conceivably leak from the slot - in which case it will have to be replaced, and that involves turing off the mains.

  anskyber 19:31 08 Jan 2008

Does it look like this? click here

  oresome 19:32 08 Jan 2008

Now if anyone has a computer problem, may I recommend Plumbing Weekly!

I think we all need to get out more............I would, but I'm that damn busy fixing all the household gadgets I don't have time.

  Legolas 19:42 08 Jan 2008

That is the type of flexible hose but the couplings are normal compression ring couplings. I have tried tightening it but it is fully tightened.

As I said it can hardly be called a leak it is what we used to call a sweat (I worked in the plumbing trade over 30 years ago so well out of the loop) I was just wondering if their was some way of stopping it without draining the system.

Thanks for all the suggestions/comments so far everyone

  Forum Editor 19:49 08 Jan 2008

if the weep is on the mains valve - the valve at the boiler end should be of the non-return type. Check to make sure it is, and then you can turn off the water mains, undo the compression valve nut, put a few turns of PTFE tape on the olive (the copper or brass ring that is compressed onto the pipe), and then retighten the valve nut. With luck that will do the trick.

  Legolas 19:54 08 Jan 2008

As luck would have it I have some PTFE tape in the house a left over from the days when I worked in the plumbing trade. We also used to use hemp and boswhite to seal the joints, I wonder if they still use it?

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