Is changing a cold water tank a diy job?

[Mrxman]

My mate had a combi fitted in his loft. Took so long for hot water to reach is kitchen sink, they used to either wash up in cold water or boil a kettle.

I can imagine. If we move ours we’d put it in the bathroom

 

[dilalio]

Put a coffin tank in.
Much better and stays clean.

 

[Razor900]

Depending on the mainsflow and site conditions I would be tempted to put a board over it for now and consider an unvented cylinder.

This summer loft temps have routinely been over 60 degrees. Perfect temp to grow bugs in the tank.

Stored water is looking a bad idea the way the climate is changing

 

[dilalio]

Depending on the mainsflow and site conditions I would be tempted to put a board over it for now and consider an unvented cylinder.

This summer loft temps have routinely been over 60 degrees. Perfect temp to grow bugs in the tank.

Stored water is looking a bad idea the way the climate is changing

Defo into a new ice age in my house...
Served my purpose now the kids are grown up it would seem.

 

[Mrxman]

Depending on the mainsflow and site conditions I would be tempted to put a board over it for now and consider an unvented cylinder.

This summer loft temps have routinely been over 60 degrees. Perfect temp to grow bugs in the tank.

Stored water is looking a bad idea the way the climate is changing

Yes there’s that too. We’ll probably get a combi boiler instead. Question is whether to do it now or later. Existing one probably has a good 7 years left so need to think it through

 

[Justin Passing]

Great diagram. Thanks , that’s really useful. It looks a lot more pro than the setup I am looking at which has an old lead pipe pointing into tank. The plastic bylaw 30 kit that comes with a new tank is that adequate?

Yes it will be fine, except it won't have the fitting for putting the 22mm vent pipe in through the top.
Many a plumber will heat the pipe so it melts a hole through the lid for itself. That's not strictly correct!

The diagram is from the water regs. I have a copy somewhere, this is the only one I could find online.

 

[Mrxman]

Yes it will be fine, except it won't have the fitting for putting the 22mm vent pipe in through the top.
Many a plumber will heat the pipe so it melts a hole through the lid for itself. That's not strictly correct!

The diagram is from the water regs. I have a copy somewhere, this is the only one I could find online.

Thank you, that's great.

 

[ChrisJP]

Stored water is looking a bad idea the way the climate is changing

I don't follow this comment. Climate change may cause more frequent water shortages and hence outages of domestic water supplies. If that happens surely storing water in a loft mounted cold water storage cistern is going to be an advantage and not a "bad idea"?

 

[Mottie]

I don't follow this comment. Climate change may cause more frequent water shortages and hence outages of domestic water supplies. If that happens surely storing water in a loft mounted cold water storage cistern is going to be an advantage and not a "bad idea"?

Nothing to do with shortages. Have you got a loft? Do you know how hot it gets up there in high summer? What do you think could happen when a tank of cold water gets warmed up? Stored water somewhere it’s not going to get warmed up enough for legionella to form is a good idea though.

 

[dilalio]

Nothing to do with shortages. Have you got a loft? Do you know how hot it gets up there in high summer? What do you think could happen when a tank of cold water gets warmed up? Stored water somewhere it’s not going to get warmed up enough for legionella to form is a good idea though.

Break tank.

 

[Mottie]

Break tank.

I haven’t a clue what that is.

 

[dilalio]

I haven’t a clue what that is.

It's what Hulk says

 

[Mrxman]

Pretty easy to DIY if you're confident with Plumbing. Get a new Cistern, (Tanks are sealed vessels, Cisterns are open), of the required size, and Byelaw 30 kit to suit. Brown Overflow, seem to recall Osma had a stage of using brown Plastic in the 70's, it could date from then! Ideally I'd say replace, if not then compression fittings are available to join new to old.

After removing existing Cistern, ensure the base is adequate to support the weight of the new Cistern. 1 litre of water weighs 1kg, so if you have a 40/25 Gallon Cistern with the 25 Gallons of water in it, that's still over 110 kg to support.

Site Cistern as required then work out where pipe entries are going to be, cut with suitable Hole Saw, fit Tank rolleyes Connectors, and couple up to original pipework. If a Mixer Shower is fitted, then ensure cold supply to this is taken from below the feed to the Hot Water Cylinder to prevent scalding in the event of the Cistern being emptied.


Once connections are made, restore supply, fill Cistern and check for leaks. When happy all is watertight, fit Lid and Insulation as required.

Do have a google for diagrams on the bits and pieces, which aren't obvious. Many of them I wouldn't follow exactly for one reason or another!

This one is from the Regs, for two tanks(/cisterns!) - obviously leave out the extras, & header arrangement. You need TWO outlet valves for H & C (C lower, as above) unless you have a separate feed to a WC, say as well.
This DOES show how the overflow fitting hangs, and using quarter turn valves, which I would, but only decent quality ones like Conex, not B&Q's cheapest.
You wouldn't use the separate cover - just make sure the plummin doesn't stop you taking the lid off.

It does not show that you have to put the VENT pipe which I added in red from eg a HW cylinder, through the top, which should also be an insect-sealed connection - ie it needs a fitting not just a hole.
Look at several illustrations.

View attachment 422228

Then there's the insulation of course. Google that. All in there are several things to get right, including the others' comments here.
Oh - put a gap in the insulation underneath to help stop it freezing - the house can warm it a little.
Don't use a BS 1212 part ONE float valve, you need a part TWO or better.

Hi Again

I have a follow up question if you don't mind regarding a new cold water tank.

I have bought a circular polytank which is the exact same size as the one we currently have (50 gallon) except the polytank has a more pronounced curve at the bottom.

The Polytank manual says the tank connector hole should be drilled 5 cm (+- 5 mm) from bottom.
Existing hole and pipework is 4 cm from bottom (which would bring any tank connector very close to the curve which may not be ideal).

Q1: is it o.k to position a tank connector higher than 5 cm to get a bit of distance from the curve?
Q2: Given that the existing pipework is positioned around 4 cm from bottom, would it be o.k to cut the pipes back a bit and then fit a plastic pipe at a slight upward slope to the tank?

Thanks

 

[denso13]

is it o.k to position a tank connector higher than 5 cm to get a bit of distance from the curve?
Q2: Given that the existing pipework is positioned around 4 cm from bottom, would it be o.k to cut the pipes back a bit and then fit a plastic pipe at a slight upward slope to the tank?

Yes, no problem.

 

[steven lee]

On Q1, a bit higher than 5 cm is fine as long as the connector sits on a flat part of the tank wall. If the hole lands on the curve the washer will not seal properly and it will weep. On Q2, yes, cut the pipe back and remake the joint with a compression coupler, just make sure the cut is square and the pipe end is clean. Once it is full, leave it a while and run the back of your hand around the connector to feel for any dampness before you box it in.