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22mm hot 15mm cold supply problem

Discussion in 'Plumbing and Central Heating' started by spiraltempest, 12 Jan 2007.

  1. spiraltempest

    spiraltempest

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    just installing a new bathroom but the pipework has a 22mm hot feed and 15 mm cold feed do i reduce down to 15mm hot when connecting to the bath and basin taps ,or just the basin ,and leave 22mm for the bath ..o and i have been out of the plumbing game for 20 years hence the no idea what i am doing questions.cheers if anyone can get me back in track most appreciated..also if i reduce to 15mm for the hot bath tap do i reduce near the bath or at furthest point........
     
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  3. TicklyT

    TicklyT

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    Do you have mains pressure cold water, and gravity hot water?
    Could make for an interesting time for the shower (whower?) mixer.

    Shower mixers generally prefer balanced pressures, but some (eg venturi mixers) are designed to use mains cold to boost the hot pressure.

    If feeds are both at mains pressure (eg combi boiler), there's probably little to gain using 22mm to the bath taps.

    If hot water is gravity, and cold from mains, then consider running a 22mm cold feed from the storage tank to the shower mixer, or possibly fit a pressure reducing valve.

    Isolating valves are useful if they are accessible. Not much point if you have to dismantle half the bathroom to get to them if you want to change a tap washer. I believe they are required now.

    Check valves may be required on the shower mixer, especially on the hot feed if pressures are not balanced. Best to see what the manufacturers say.
     
  4. spiraltempest

    spiraltempest

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    cheers yes cold 15mm from mains,and 22mm hot direct from the combi ,all pipework is in place just been capped of as someone stloe the old plumbing (copper), i dont need to fit a shoewer though might just put taps on,cheers
     
  5. spiraltempest

    spiraltempest

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    so do i just leave the hot at 22mm for the bath or reduce to 15 mm cheers
     
  6. jumbo55

    jumbo55

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    dont complicate things spiral, am i to understand you have two tails coming out of the floor where the bath is to be, one 22mm one 15mm mains, combi boiler, no shower going in. 2 taps. even mixer. just run 22mm to hot, and 22x15 reducer to cold, put the reducer to the cold where its comfortable for you to fit, and get some short flexible connectors with isolating valves. the problem most plumbers will see is if your hot is from old combi and not very good and you put a very strong mains pressure through a mixer tap, will the cold push the hot back. but with the set up you have got with no shower, i dont envisage that problem, as you will simply put hot water in first from your combi, wait 30 mins for it to fill up by which time it will be cold enough for you to get in. its a bit daunting when you been out the game so long. just wrap your threads, wrap your olives, use your silicone or plumbers mait and make sure everything tight.
     
  7. Softus

    Softus

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    Don't wrap the threads on compression joints or tap tails.
    Don't wrap the dry side of olives.
    Don't use silicone on any joint on a supply.
    Don't use plumber's mait on any joint on a supply.
     
  8. jumbo55

    jumbo55

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    the bloke used to be in the game, so give him some credit for knowing what goes where. he is just lacking a bit of confidence. i wrap olives with ptfe always. i wrap my gas joints with ptfe(copper to iron) never a leak. i didnt suggest using silicone or plumbers mait on threads, but the bloke is setting up a bathroom. one assumes he better have it handy for his taps and waste.
     
  9. Softus

    Softus

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    Fine - credit duly given.

    Fine - I didn't suggest not wrapping, I wrote "Don't wrap the dry side".

    Well done.

    Er, nor did I. And I didn't say that you suggested it, but you have a narrow-minded view of who else might be reading your 'advice' and who might misinterpret it.

    You make lots of assumptions, for example that the OP is a bloke. And why in the name of all that's holy would you put Plumber's Mait near a tap? Unless of course it was your aim to make it difficult for someone else to remove the tap when it needs replacing. :rolleyes:
     
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  11. jumbo55

    jumbo55

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    softhead says

    Don't use silicone on any joint on a supply.
    Don't use plumber's mait on any joint on a supply

    er!! I didnt suggest this.

    softhead says

    would you put Plumber's Mait near a tap? Unless of course it was your aim to make it difficult for someone else to remove the tap when it needs replacing.

    ive always put a smattering of plumbers mait under a tap, if you knew anything, you would know its non setting so why then would it be hard to get the tap off.
    maybe for you.

    my answer was to the person who directed the question, nobody else.
    you not only seek to belittle me with your comments, you then go on to tell me the OP could be a woman. the answer would be the same wether man or woman, if i were a betting man, i would have assumed a bloke.

    however i would put a bet on you being a woman definitely, nitpicking and going off the point. if you are a man, tell me, was it your wife that nicknamed you softus. does she call you that all the time or only in the bedroom. dont mind a bit of friendly banter softus, but i am new to this site and it really gets my goat when engineers in the same profession, instead of discussing why they do certain things and how its better, just up and proclaim themselves know alls and everybody who differs is no good. my trade nowadays is 98 per cent gas but i am a time served plumber, and no advice i have given could be regarded as dangerous or bad practice.

    too much slagging off on this site. should be a forum for the exchange and learning of knowledge for customers and engineers. not the plumbers answer to the houses of parliament.
     
  12. Softus

    Softus

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    We've dealt with this already. :rolleyes:

    No - I asked why, not "would you".

    That's why I observed that you're narrow-minded - because you don't consider other readers, of which there are potentially many.

    I don't seek to belittle you - my initial post wasn't even directed to you, but you chose to take it personally.

    The OP could be a woman - why not? Why assume, or bet?

    I don't know it all, or claim to, or pretend to. I merely listed four 'don't' points for the benefit of both the OP and anyone else reading the topic. If you disagree with any of the things I listed, then why you don't you explain why you think I'm wrong, instead of nitpicking (sic.).

    Then maybe you'd best leave the watery jobs to general plumbers. :idea:

    :idea:

    :idea:
     
  13. jumbo55

    jumbo55

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    wrong time of the month for you is it?
     
  14. Softus

    Softus

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    :idea:
     
  15. croydoncorgi

    croydoncorgi

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    ANYONE considering how best to do compression joints should read what the MANUFACTURERS specify.

    In the case of compression joints under 35mm, I believe the advice is 'use NOTHING except small amount of mineral oil for lubrication'. Jointing compunds are only recommended for larger sizes.
     
  16. jumbo55

    jumbo55

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    yes well i started ptfe on the olive when the italian fittings used by my local council whom i worked for, kept leaking after a couple of months, its a habit i got into, its a habit i intend to keep up, its not bad practice, and i reckon it saved me time on callbacks which meant for a happy customer.
    if its good enough for 35mm and above, its good enough for the smaller joints. so carry on croydon, i wont knock you, we all work different, as long as its safe, whose to say anybody is right and wrong, it might appear to be belt and braces to you, i dont care, i do it how i have always done it.
    and if your experience is different, then you carry on.
     
  17. Softus

    Softus

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    This is fine and dandy for making new fittings onto new tube, but it's an imperfect world that's full of imperial pipe, paint streaks and solder snots. Many people use either jointing compound or PTFE tape to overcome these imperfections.

    I agree with jumbo55 that if you have a way of achieving leak-free (and easily maintainable) joints, every time, then you should stick with it.
     
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