Hot water cylinder leak - advice please

[phil090207]

Hi, my indirect vented hot water cylinder has just started leaking slowly (4 drops per minute) from the upper coil connection. I think I bashed the pipe and started it

The water is coming out between the threaded pipe and the nut on the tank, as shown by arrows in photo:

Untitled

• phil090207
• 16 Jan 2014
• 1

What is the likely cause of this leak please? Is it heating circuit water or tap water which is leaking? Will I need a new cylinder or can the connection between coil and cylinder be repaired? Is there any point trying to tighten the nut on the cylinder (I'm guessing this would only turn my slow leak into a fast one!?)

If I have to replace cylinder is there a temporary fix that will last a month or so?

By the way, its possible copper corrosion has occurred in the past - we have private (borehole) water which is acidic, we installed a filter to correct the pH when we moved in 7 years ago (pH is 7 now, I just checked it), but the cylinder is older than that.

Thanks for some advice, Phil.

 

[Agile]

It looks like being tank water.

Tightening the nut may cause a worse leak.

There was a recent thread which gave all the details of how to try repairing . But that's tricky and not what I would ever recommend to a Diyer.

A replacement tank will be the sure solution. But you could try a repair or call a plumber to try for you.

Tony

 

[phil090207]

Many thanks for the help Tony. Should I go for copper or steel for replacement tank?

Reviewers on Screwfix site seem to like their steel tanks because they have easy 22mm connections?

Phil

 

[Agile]

I also like the stainless tanks because they are lighter to handle.

But you MUST use the correct immersion with ALL parts made from Incaloy ! Those sold by Screwfix are NOT suitable!

Tony

 

[phil090207]

Tony do you mean I shouldn't use the Screwfix Incoloy immersion heaters such as this? It says suitable for stainless steel cylinders.

http://www.screwfix.com/p/27in-incoloy-immersion-heater/57798

 

[Happyplumber]

That Immersion is perfectly suitable for stainless steel cylinder

 

[Agile]

If it were exactly as it the photograph then it would be suitable.

But a few months ago when I checked the ones that Screwfix ( and Toolstation too ) were selling had a copper pocket for the stat.

In fact rather oddly I bought some from City Plumbing and they had just a few out of their stock all with the same makers name but only a few with incaloy pockets.

Tony

 

[gas112]

Drain heatin and drain cylinder undo the nut and re washer it using a fibre pump washer that will do it

 

[phil090207]

Thanks for suggestion gas112 but I really don't want to have an emergency cylinder change on my hands if I have problems with the fix. I'm a DIYer so I need plenty of planning and shopping time...

Also the cylinder I have is oversized - its a 170lt, I don't see the point of storing more than 100lt when its so quick to heat more.

So I think I'll get a new steel tank, probably a Screwfix Aquastel one. I've read steel is more corrosion resistant and we potentially have acid water (if the filtration is less than perfect).

In the meantime I've hopefully fixed the leak temporarily with B&Q Epoxy Putty for Metal. Just by closing the cold feed valve and opening a hot tap, I stopped the drip. Then I cleaned up the cylinder nut and thread with steel wool and white spirit. Stuck the putty all over the nut and left it a few hours. Cold feed back on now and no drips. Hopefully that will hold it for a little while.

 

[Agile]

Stainless is less affected by corrosion.

But the metal is very thin indeed too. That's why they are so light to handle which is why I like them.

Perhaps you need a pH alarm on your supply?

How does your pH corrector work?

Tony

 

[phil090207]

Tony, we have a big blue cylinder containing pH correction medium (calcium carbonate I believe) which the borehole water passes through on its way to a large loft storage tank. We used to have media in there to remove iron and manganese too, but the filter back-washing wasted so much water I took it out and now just use the pH medium which doesn't need backwashing.

I check water pH with a digital meter from time to time, it's been at least 7.0 since we've had the filter. So I don't think corrosion should be a problem now, but the copper cylinder was there before we installed the filter.

I went to Screwfix today to collect my "Collect Next Day" Aquastel cylinder, but it wasn't there as promised so I have to go again Monday. Grrr.

Good news is the epoxy putty has fixed the leak. This is good stuff.

Phil

 

[Agile]

You may find that Screwfix give you a £10 voucher or something when a collect next day fails!

Your CaCO³ is a very cheap and simple way to neutralise acidic water as long as the water flow is not too fast through it.

Iron in water can be particularly difficult. The borehole at my house in Lagos suffers very badly from that and stains the baths and basins.

Tony

 

[xr4x4]

I'm sure the screw fix incaloy elements are just sprayed silver..!

 

[Agile]

That would not surprise me at all!

 

[phil090207]

I have a screwfix 27in incaloy heater in my hand, I can confirm the thermostat tube is made of the same grey metal as the element, definitely not copper or silver paint

I notice the one Wickes is selling has a copper stat tube though, in the photo at least...

I wasn't offered £10 or anything else by screwfix, and its not the first time I've been there and my order wasn't in. Last time they called to warn me, this time they didn't. Fortunately I'm not in a rush thanks to epoxy putty!