Moving hot water tank to loft ??

Discussion in 'Plumbers' Talk' started by duncan10000, Sep 7, 2012.

  1. duncan10000

    duncan10000 Member

    Hi all,

    I've done a search  but just wanted to be sure..

    I've just purchased a house which has a hot water tank in an airing cupboard on the landing. There's a gas boiler downstairs in the kitchen which i assum heats the water to store in the hot water tank (in-direct) ??

    I want to move the hot water tank up into the loft to free up this cupboard space.

    Is this an easy process as long as i've got enough head height to keep the cold water tank above the hot ?

    I was planning on moving the tank into the eaves within an insulated box with all pipework well lagged & then have the cold water tank up in the middle (highest point).

    Does this sound reasonable ??? & does anyone have any idea how much a plummer would charge or is it a diy jobbie as i can easily extend the current pipework, build a solid frame for the tank etc... ??

    Cheers - Duncan
  2. G Brown

    G Brown New Member

    In therory it is do-able. Weight and wall loadings is the major consideration. Also the roof must be strong enough to take the massive weight of a water tank  - it must be floor supported, NOT hung off the roof beams. Is you loft opening wide enough?

    Better still fit an unvented cylinder in the loft then there is no need for a storgae tank.....or just fit a combi boiler?
  3. duncan10000

    duncan10000 Member

    Thanks for the reply.

    Is an unvented cylinder just 1 tank that has the cold on top (think i've seen these) ? If so would this be a simple job of just extending the existing pipework up into the loft ?

    Or is it worth fitting a pressurised tank (mega-flo) or is this loads of work ? (i know the cylinders are more expensive) ?

    Loft hatch is quite large but i'd happily make larger as going to be re-plastering etc..

    thanks - dunc
  4. palavaman

    palavaman Well-Known Member

    Is an unvented cylinder just 1 tank that has the cold ontop ......  NO

    Or is it worth fitting a pressurised tank (megaflo) ........ THAT IS AN UNVENTED CYLINDER.
    There are important safety features incorporated into an unvented cylinder. Normally fitted by special peepol who carry a certain G3 tkt.
  5. Crowsfoot

    Crowsfoot Screwfix Select

    I have often moved CWS tanks into the loft in order to free up space and also improving the static head for the hot water.
    However, moving the hot water cylinder up there as well is a bit of an unproffesional thing to do (think I've done it once in 40 years of plumbing), loss of the static head being the main reason not to along with a host of others.
    I don't think it's a job for a diy either.
  6. Onetap

    Onetap New Member

    You'd need to raise the cold water storage tank above the vented cylinder and it would probably still suck air in down the open vent when you drew off hot water. I wouldn't do it.
  7. duncan10000

    duncan10000 Member

    Thanks all.

    If it's a no no to move the hot water cylinder into the loft then maybe I should get a megaflo or similar??

    Anyone have a rough idea of whats involved to fit one & very roughly what a plumber would charge to fit directly above where the current hot water cylinder is?

    I could do the donky work, make a frame & extend pipes if need be.

    Thanks - Dunc
  8. wetpants

    wetpants New Member

    Cheapest option is as Brownose advised is a Combi Boiler,why dont you consider this. Fit in the roof space if you can.
  9. duncan10000

    duncan10000 Member

    Do you mean to get rid of the boilerstairs and the hot water cylinder and replace with a combi boiler so it only heats as water passes through it? If so then this is the setup we had at our last house & although i'm sure it's very efficent, when you want to have a shower and a tap/washing machine etc.. is on then i'm sure even the best combi's couldn't cope??
    I of course could well be wrong but thought that a big maxiflo type cylinder was the way to go ??
    thanks - dunc
  10. You're right, Duncan.

    You can get powerful combis which are reckoned to handle more than one hot water outlet at a time, but it does depend on you having very solid mains water pressure and flow first. Since you've tried a combi before and found it wanting, then you are the best judge of whetehr it's suitable for your current home. It's certainly the most space-saving solution, tho'!

    (Mind you, modern combis are pretty effective and can give decent flow rates - can you remeber what model you had in your last home?)
  11. sam spade

    sam spade Active Member

    But they can't perform miracles. If the cold water flow rate is 10 litres/min you can fit the biggest combi there is and the flow rate will still be 10 litres/min.

    Mains connected unvented cylinders can have the same problems as a combi for the simple reason that both are taking water directly from the mains; it doesn't matter that the cylinder has 200 litres in it. The only reason water comes out of the tap is that the mains pressure is putting water into the cylinder. So the flow rate will be dictated by the cold water flow rate and pressure. The only advantage of a mains connected unvented cylinder is that you do  not have to heat the water instantaneously, so the boiler can be much smaller.
  12. Cheers, Mr Spade. I did, for that reason, qualify my comment with "...but it does depend on you having very solid mains water pressure and flow first."

    I did wonder if the same thing applied to 'megalflow' units - it made sense that they were governed by mains water flow, so cheers for confimring that. In which case, why are some plumbers on here praising them from the rooftops?

    When you consider their extra expense, the extra room they take up, the need for a particularly qualified peep to instal it, the additional running cost from having stored hot water, and finally the pitiful extra gain in performance for the vast majority of us, why would peeps choose them instead of a powerful combi?

    I wouldn't.

    Oh, I haven't...

    (Ok, 'powerful' is pushing it a bit, but hey...)
  13. wetpants

    wetpants New Member

    Just go back to Browns and Wetpants comments, its already been said ***
  14. G Brown

    G Brown New Member unvented cylinder delivers balanced supplies to multiple does not go cold when someone runs another tap. Of course they have flow/pressure requirements but if the install is in spec they are simply superb.
  15. duncan10000

    duncan10000 Member

    So can i just double check...... as getting conflicting advice.
    If I move my hot water cylinder into the loft, and as long as I keep the cold water tank well above the top of this then all should be fine ??
    My understanding is that water pressure to the taps is calculated from the cold water tank > tap height so if I raise the cold water tank then all should be good ??
    I will of course insulate the hot water cylinder and all the pipes as understand it's more prone to heat lose in the loft.
    Cheers - Duncan
  16. G Brown

    G Brown New Member

    In theory  - yes.

    In practice ( weight, loading, sufficient head, venting ) maybe no.

    Without seeing and measuring it is impossible to say.

    You hot water cylinder should be insulated anyway! If its an old one it will be damaged when you move it.
  17. Duncan, in theory and practice, yes. Provided you can give your cold tank good head and all the stuff GB says above.

    With a vented system - such as you currently have - it is essentially the CWS wot provides the water pressure and flow to the taps. In theory raising the hot cylinder shouldn't affect this at all. However, raising the hot cyclinder closer to the CWS tank level can cause other problems as outlined by Onetap above - if the CWS isn't providing good head to the hot tank, then there is a risk that when you draw off hat water - which comes from the top of the hot tank - it will instead (or also) draw in air from the expansion pipe wot is also exiting from the top of the hot tank and looping over the CWS. This is because the CWS isn't positioned high enough above the hot tank so isn't delivering enough pressure to the hot tank.

    Bottom line - how lofty is it up in your loft? If you place your hot cylinder on the floor up there, can you then lift the CWS a good few feet above the top of this tank?

    I don't know what a "good few feet" means in practice - hopefully a plumber on here will give that info. But, as Onetap suggests, if you asked a plumber to do what you suggest they might well be reluctant to do so cause if it starts drawing in air when you run the hot taps, they'll be the ones getting into hot water.

    And if you ever fit a pump to the system to provide a better shower, then the problem is magnified.

    So, afaIk, it all comes down to how high you can get the bottom of the CWS above the top of the hot cylinder.

    You should also be looking at positioning the hot cylinder above a supporting wall in the floors below - a CWS is bludy heavy; a hot cylinder more so.
  18. duncan10000

    duncan10000 Member

    Thanks for the replies & thanks for explaining DA :)

    I wanted to move the hot water cylinder to give more room on the 1st floor before ripping out the bathroom & re-doing but by the sounds of it i'm best to just leave it as it is. The roof in the attic is high as it has a steep pitch so could probably get the cold tank high but it would be a right pain supporting this.

    Are hot water cylinders with a separate gas boiler a good system for quite a large house as i've only ever had combi's before which as above always seemed to struggle with more than 1 shower/tap on at once?

    I suppose it depeneds on the size of the cylinder & water pressure/head ??

    Cheers - Dunc
  19. If your attic has a steep pitch, then fair chance you'll be able to make it work - tho' a pro on here (or a plumber you contact) would really have to confirm what sort of height is needed.

    I think fitting your CWS higher will be the least of the tasks - you can get long 'coffin' tanks that you can squeeze right up into the appex of your roof - supports will be taken from joists spanning the rafters and supported by a few uprights. Because the tanks are long, the weight is distributed, so rafters ain't gonna feel it*. That's realatively easy. You can fit a number of tanks, all linked together. Making sure your hot cylinder - wot has a small footprint and will therefore rerquire much more localised support - is secure is another matter, tho' not rocket science.

    What do you mean by "Are hot water cylinders with a separate gas boiler a good system for quite a large house...?" . Isn't that what you've got? Is it not running at present? To answer your Q, yes, it's a good system for a large house as the cold and hot supplies are taken from different connectors on the CWS so won;t affect eachother. As long as your mains water supply is up to replenishing the CWS, then you can in theory draw as much water from as many outlets as you want. All things being relative. You can add a pump to give a power shower, etc.

    Have you had your mains water pressure and flow measured? You can do a basic test yourself - stick a bucket under your kicthen tap, turn it on full for 10 seconds, and measure how much water is in there. Times that quant by 6 to get litres-per-minute. (Or you can do it for only 10 seconds if you wish, of course...) What do you get?

    *That's what I think anyways...
  20. duncan10000

    duncan10000 Member

    Yep... we currently have the hot water cylinder with separate boiler but as i've only just bought the house & not living there yet & haven't had this type before so didn't know if it's a good way of heating water. Only has combi's in previous houses.

    Think i'll just leave it all where it is as 'if it ain't broke, don't fix it'. It's has 2 bathrooms upstairs and currently has an electric shower in one & then a mains powered in the other. Think i'll keep this sort of setup but maybe changed the mains fed to a power shower using a pump.

    On one last note.. & just so i know. How does the central heating work with the setup we've got (hot cyclinder & gas boiler) ?? does the gas boiler just heat the water for the rads with a pump & it's nothing to do with the cylinder ??

    Thanks again - Dunc

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice