Dripping Overflow Pipe

[dk1uk]

Hi - the overflow pipe that comes from the cold water tank in the loft is dripping onto the path outside.

I have noticed that it drips after we've used hot water (showers and baths). It's not a massive problem, but the overflow pipe is right above the back door so it's annoying. At worst, it's a drop every 5 seconds or so.

I've checked the water level in the cold water tank at these times and the water level is definitely not high enough to be causing this dripping.

We have a sealed system boiler and this was installed last year (replacing/removing the hot water storage tank in the loft).

I am baffled - can anyone shed any light as to what might be causing the problem? Condensation?

Many thanks

 

[Belboz]

When you checked the cold water tank after seeing the dripping, how close to the overflow outlet was the water level??

 

[dk1uk]

Hi Belboz

Yes - and it's a good couple of inches below the overflow so it's definitely not the water in that tank causing the dripping. And it seems to only happen when we've used lots of hot water - does this sound likely?

Thanks

 

[Belboz]

I assume the overflow pipe is JUST for the cold water tank and there aren't any other pipes feeding into the same overflow?

Normally, there is just the one overflow outlet from the cold water tank - a single pipe going through the wall.

However, I have seen an F&E overflow tee'd in to the cold water tank overflow but this is unusual and I suspect you no longer have such a thing.

 

[dk1uk]

That is something I will need to check tomorrow. The F&E tank had it's own overflow pipe which has now been removed when the new boiler was installed.

I can't imagine there's anything else that could feed into that pipe but I'll get up there tomorrow and double-check.

Thanks again.

 

[Armo74]

Probably down to the mixer taps back feeding the hot water into the tank.

 

[dk1uk]

Hi Armo - what would be the cause of that? Is it something that I can easily check?

Do you mean that water is being fed back into the cold water loft tank which in turn is causing an overflow?

 

[Armo74]

Next time you run the bath check the tank and overflow.
If it drips you need to fit check valves on the hot and cold supply.
(Assuming that you are running both hot and cold at the same time through the mixer).

 

[dk1uk]

Thanks. I have just run the mixer tap in the bathroom and yes the overflow starts dripping. I'll take a look at the loft tank tomorrow and see what's happening.

In terms of fitting check valves, is it an urgent problem would you say? I'll need to figure out how brave I am to attempt this myself! I can easily turn off the hot water feed at the cylinder and hopefully there's a valve at the cold water tap to turn off that feed. Then presumably, cut the pipes, insert valve and job done?

One problem I can see is that I think that the same occurs when we run the shower - pipework behind tiles - is there any alternative if I don't want to re-tile?

Many thanks for your help.

 

[Armo74]

Just get it done as soon as.
You need to trace the pipework,how hard it is to do what you need will depend on how the shower and bath have been plumbed.

 

[dk1uk]

Hi – having checked, it seems that I already have check valves installed.

I have been up to the loft and I have a question about my float valve.

Normally water comes out from the valve at the bottom, however I noticed whilst fiddling with it today that sometimes water is spraying out of the top. The valve is very close to the overflow and so I wondered if this spraying might be causing my dripping overflow pipe.

Should water be coming of the valve here - see picture, I have drawn an arrow.

Many thanks

Valve

• dk1uk
• 17 Aug 2014
• 1

 

[Armo74]

Get someone to run the hot tap whilst you are in the loft and see if it is spraying out the overflow.
If that is the case then the dripping should stop once the cistern is topped back up and the float valve has closed off the supply.
You sure they are check valves and not isolation valves?

 

[dk1uk]

OK, thanks, I will get back up the loft.

I think they are check valves - at least they have arrows on them like other check valves - here's a pic.

Should water be spraying out the top of the valve like that? Or might it be damaged?

Untitled

• dk1uk
• 16 Aug 2014
• 1

 

[JimCrow]

OK, thanks, I will get back up the loft.

I think they are check valves - at least they have arrows on them like other check valves - here's a pic.

Should water be spraying out the top of the valve like that? Or might it be damaged?

Untitled

• dk1uk
• 16 Aug 2014
• 1

they are isolation valves in the pic

to save removing tiling etc. fit a 3/4" swing check valve on the hot water draw off in the cylinder cupboard.
http://www.bes.co.uk/product/98~PL~1732~-Swing-Check-Valves-.html

you will need two of these also 6672
http://www.bes.co.uk/products/140.asp?EPBOE=#6672