Why have a Cold water storage tank and cylinder with a combi boiler?

31
Found 1st Apr 2016
Recently moved to a new house and it has a Ideal Logic 24 combi boiler, however i also have a Cold Water Storage (CWS) tank in the loft and a hot water cylinder in a cupboard below.

Can anyone inform me why?

As far as i was aware with a combi boiler the CWS and cylinder became redundant and could be removed, however mine are still in use (well have water in them at least)

TIA
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AskBoilerStorage
31 Comments
just due to the size of water tank and effort involved in removing it,
LOL, thats what i though. As long as its not costing me anything extra to run, i'm not really bothered although if the cylinder tank could be removed it would free up some decent storage space.
If your water is switched off for any reason by the water board you still have some lying around in your tank to tide you over.
paully

If your water is switched off for any reason by the water board you still … If your water is switched off for any reason by the water board you still have some lying around in your tank to tide you over.



Stagnant water
paully

If your water is switched off for any reason by the water board you still … If your water is switched off for any reason by the water board you still have some lying around in your tank to tide you over.



Would i still be able to get hot water coming through the boiler or would i have to switch the immersion on?
mclovin9091

Would i still be able to get hot water coming through the boiler or would … Would i still be able to get hot water coming through the boiler or would i have to switch the immersion on?



I think it is meant as if you had a power cut, you would still have hot water to wash/bathe with.
Kaos_KS

I think it is meant as if you had a power cut, you would still have hot … I think it is meant as if you had a power cut, you would still have hot water to wash/bathe with.



Surely not otherwise i'd be constantly heating the water in the cylinder as a "just in case".
Well one compelling reason is so you can have a power shower. A 24kw combi will have a miserable hot water flow.
Yeah tell me about it

Wait what? I have a power shower but the flow rate is rubbish.
Edited by: "mclovin9091" 1st Apr 2016
Well there will either be a diverter valve so the combi fills the tank or it may just be an immersion on the tank for the shower.

Hmm, i've been away for a few days and turned the hot water off to check exactly that. (i suppose i should have mentioned that originally)

But i had hot water from all taps and the shower, thats what prompted the question as i think the CWS and cylinder are pointless.
mclovin9091

Hmm, i've been away for a few days and turned the hot water off to check … Hmm, i've been away for a few days and turned the hot water off to check exactly that. (i suppose i should have mentioned that originally)But i had hot water from all taps and the shower, thats what prompted the question as i think the CWS and cylinder are pointless.



Well maybe it just lazy people. I'm guessing the hot water tank is steel and not copper. I've never known a copper one be left.

So does the immersion work?
It does for the heating, but presumably not for the water.

I'd agree with the lazy part, i think i'll check if its copper probably is and then i'll go around the neighbours and help them remove theirs for extra storage space of course

In theory tank & immersion should be redundant. They may still serve some fittings if boiler installer couldn't reply back to new boiler. If immersion is off & you're getting hot water to all taps then boiler is feeding to hot taps & immersion is redundant, however water tank might still supply something e.g. A toilet. Try running cold taps & flushing Loo to see if tank empties & then fills up
Oh, and check type of shower, you say you have a power shower, is this just a pump on your incoming hot & cold feed, & if so where is it fed from, or does it heat the water as well? If it heats the water it will have a separate cold water feed, this could either come directly off mains or via water tank, my suspicion is that something is still being fed by tank.
Ps I'm confused about immersion being used for heating, the combi boiler should be doing that.
Check if your electric meter has a blue or black button for cycle display or two reads showing. It may be that the house was heated via a storage heater but these aren't needed if you have a combi.
_tsurt_

Check if your electric meter has a blue or black button for cycle display … Check if your electric meter has a blue or black button for cycle display or two reads showing. It may be that the house was heated via a storage heater but these aren't needed if you have a combi.



Off the top of my head its black. Will check in the morning.

Jan6767jan

Ps I'm confused about immersion being used for heating, the combi boiler … Ps I'm confused about immersion being used for heating, the combi boiler should be doing that.



Hell i'm confused as well. There are 4 settings on the slider on the immersion. Off, On, Timed and once. All functions work as they should.
I'll take a couple of pictures tomorrow of the jungle of pipework in the airing cupboard for all to have a laugh at.

Anyone seen a flexi pipe with 2 shut off valves in an airing cupboard before?
Could the immersion heater be used for a shower, and the CWS header feeds the immersion - higher supply required for the shower that the mains incomer wouldn't be able to meet through small bore tubing?
Wedge up the ball valve in the cw tank before having a shower and see if the level has dropped after.

I reckon cootuk2 has hit the nail on the head
You can fit a combi and run it as a system boiler, often using the hot water from it to supply a nearby tap.

It can be done for a few reasons, for example to remove a long pipe run to a hot water outlet, or just because the combi version of the boiler is cheaper to buy than a system boiler.
cootuk2

Could the immersion heater be used for a shower, and the CWS header feeds … Could the immersion heater be used for a shower, and the CWS header feeds the immersion - higher supply required for the shower that the mains incomer wouldn't be able to meet through small bore tubing?



Doubt it as i would only have had cold water last night.
chocci

Wedge up the ball valve in the cw tank before having a shower and see if … Wedge up the ball valve in the cw tank before having a shower and see if the level has dropped after. I reckon cootuk2 has hit the nail on the head



As i said, i doubt it but will do so and then be more confused as to how the hell i was getting hot water last night
Right pics as promised, hopefully some nice person can clear things up.

http://s258.photobucket.com/user/mac9091/media/Randoms/IMG_20160402_103119609_HDR.jpg.html][IMG]http://i258.photobucket.com/albums/hh275/mac9091/Randoms/IMG_20160402_103119609_HDR.jpg[/URL][/img]

Right there is two pipes going into the (copper) tank on the left side and one on the right. There are six pipes going to the loft. As a side note (on laziness) i have redundant two copper pipes just sitting in my bedroom cupboard as they have clearly been cut just below the ceiling.

http://s258.photobucket.com/user/mac9091/media/Randoms/IMG_20160402_103108745_HDR.jpg.html][IMG]http://i258.photobucket.com/albums/hh275/mac9091/Randoms/IMG_20160402_103108745_HDR.jpg[/URL][/img]

The upper switch goes to a control on the top of the tank and the lower switch controls the Potterton unit as seen below.

http://s258.photobucket.com/user/mac9091/media/Randoms/IMG_20160402_103139650_HDR.jpg.html][IMG]http://i258.photobucket.com/albums/hh275/mac9091/Randoms/IMG_20160402_103139650_HDR.jpg[/URL][/img]
Well the top one controls your immersion (should have its own feed so should have a fuse in the fuse box, probably 16A) the second is for the thermostatic controller and the electronic diverter valve (white box sat on the pipes).

So as you currently live without using it one of two is likely. Either someone has been lazy and not removed it all (just swapping out a wall mounted boiler with a combi) or it is live but locked out the current loop so say if you had no gas/boiler broke you could use the immersion to heat water.
But without being there and working out the flow it's hard to tell.
thanks for the help really appreciated.

I'd guess that the immersion can be used as a
back up due to the flexi pipe having a tap on it, which is currently closed. (you might be able to make it out in the top left of the 2nd pic)
*top center
Its a combi fitted as a system boiler. I'm assuming the hot from the boiler just feeds a single tap, or perhaps the shower.
mclovin9091

thanks for the help really appreciated.I'd guess that the immersion can … thanks for the help really appreciated.I'd guess that the immersion can be used as a back up due to the flexi pipe having a tap on it, which is currently closed. (you might be able to make it out in the top left of the 2nd pic)


The flexi pipe is how you fill up the closed system to the boiler (radiators), nothing to do with the hot water to the taps.

Edited by: "pinkleponkle" 2nd Apr 2016
My mums old fireplace had a cylinder behind it that heated the water for the hot tank, so the immersion didn't need to be on when a coal fire was burning, could this be the case?
Also, you could ask the estate agent if they know anything.
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