Cylinder Problem

[rustyh]

Hi,

Looking for some help with an issue I have with my water cylinder.

The currently cylinder is one of the double tank types, I think the bottom tank is the hot water part and the top tank is the header tank (cold water)
It seems to be constantly over flowing (via the overflow pipe). Ive checked the ball value and that seems fine (no leakage when in the off position).
From what I can see there is sometime a back flow from the bottom tank up to the header tank (via an internal pipe link).

From what Ive read, this can be caused by heating coil being knackered and leaking in to the tank (the cylinder is about 19 years old!).

Assuming the cylinder is no good, I wanted to check if I needed to replace like for like, I.E do I have to replace with one with a header tank.

The reason I ask is there seems to be a small black plastic header tank that feeds the cylinders header tank, and could really understand the need for two.
If the black plastic header tank is sufficient, I will just get a bigger main tank

 

[stardanny]

What boiler have you got?
Small black tank might be for heating. Is it higher than cold water tank part of cylinder?

If the cylinder has a leak thru coil, it is knacker.

Can put in standard indirect cylinder and large cold water tank, if you have a loft.

Or think about getting a combi.....?

Daniel

 

[Steelmasons]

Possibly an Elson unit/harcopack?

 

[rustyh]

The boiler was originally a Glowworm Ultimate (I think a 50), but it was replaced with a Baxi Solo 15HE last year (no changes to pipe work were made)

Thought Id better take a picture of the cylinder just in case. But the small black header tank looks like it feeds both the cylinder and the heating system

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• rustyh
• 28 Mar 2014
• 1

 

[stardanny]

What make you think it feed both from small header tank? The tank on top of cylinder normally feed from main cold water. Your cold feed for bathroom, is it from main cold water?

Can you take a pic of the black tank and it pipework please?

Daniel.

 

[rustyh]

Thought Id better get some images on the go to explain what the pipework looks like

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• rustyh
• 28 Mar 2014
• 1

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• rustyh
• 28 Mar 2014
• 1

 

[stardanny]

The main cold feed is feeding both the tank above cylinder and black tank, that is correct.

Where do the pipe that gone from isovalve to the right in bottom pic?

Your diagram of pipework might be wrong, the pump should be between boiler and motorised valves.

It look fine but....the shower pipe, is that feeding from feed & expansion black tank only for heating? I hope not

Daniel.

 

[rustyh]

Hi Daniel,

The pipework to the right of the picture is just blanked off, I think its old pipework for something, but its not been used for ages

You right, I messed the diagram up slightly as the piping by the boiler is behind junk and couldnt quite see it, Ive rechecked it and redone the diagram (see below)

The shower pipe feed the shower from the black expansion tank yes, its goes from the black expansion tank and to a shower pump by the looks of it, then off to the shower. Same with the hot, the hot comes out of the cylinder to the other side of the shower pump them on to the shower.

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• rustyh
• 28 Mar 2014
• 1

 

[rustyh]

Do I need to change some of the pipework you think?

 

[Norcon]

It might be the cylinder coil knackered.
If it was disconnected and pressure tested you would know.

 

[Whitespirit66]

Maybe a mixer tap backfeeding into hot water cyl. Kitchen mixer is a favourite, as supplies are usually gravity hot from cyl, and mains cold.

If you have iso. valves on pipes to mixers, try turning them off and seeing if cyl is still overflowing. It's an easy check to do and simple to rule out before focusing on the cylinder.