1. Visiting from the US? Why not try DIYnot.US instead? Click here to continue to DIYnot.US.
    Dismiss Notice

New mains gas supply + boiler +other appliances+ pipe sizing

Discussion in 'Plumbing and Central Heating' started by diyerdude, 4 Oct 2012.

  1. diyerdude

    diyerdude

    Joined:
    3 Oct 2012
    Messages:
    5
    Thanks Received:
    0
    Location:
    London
    Country:
    United Kingdom
    Hello,

    Looking for some assistance to get the the job done right first time.

    I moved to a property that had only electrics. Gas was cut off years ago. Got National Grid to check the steel cap off pipe and no gas as its been cut off from outside.

    I have been trawling forums and been unable to find answers to questions I have been hearing from others. Just bits and pieces.

    Basically, 3 bed house with planning to extend double storey on side (when it gets done). I have been to sites like vallaint and Worcester Bosch system finder and they recommend 37kw boiler as I put down 2 showers (opted for combi as used to it)-(vallaint recommend CH requirement as 40kw). I also need to put a 5 burner hob and double oven totalling to 16kw and gas fire ranging 5-6.5kw. This totals to 59.5kw

    The boiler position is going to be upstairs airing cabinet where the hot water tank was - only option as no space in small kitchen.

    I have seen National Grid (NG) working on the main road and all they seems to be doing is pushing 22mm pipe through the steel pipe to peoples homes. I have heard from other people inc installers that when new boilers are installed the 22mm incoming is not sufficient and has been causing gas out situations. So they have to switch off one appliance to keep the other going and call NG again.

    Can is ask NG to install a bigger pipe as in the application forms there is no where to indicate the potential usage so they can install the right size in the first place rather than dig up every thing again second time.

    I have also been trying to get the pipe sizing so that when I get installers they can put the right size rather than guess work, as many of the posts in here and elsewhere say they have got installers for quotes and do a guess work rather than try and get the sizing right first. Would it be possible to some to tell me the size of the pipes, if I were to give the lengths and position of the appliances?

    Of course a good installer would do the this but they are hard to find and quite busy. My friend recommended his installer but his quite busy and not available for a quote till 1.5 months away and for the work it would be longer and thats too far away as need heating as soon as NG has laid the pipe.

    Any help appreciated.
    den :oops: :mrgreen:
     
  2. Sponsored Links
  3. Agile

    Agile

    Joined:
    26 Jun 2004
    Messages:
    63,560
    Thanks Received:
    4,511
    Location:
    London
    Country:
    United Kingdom
    If you must have a combi boiler then the heating is irrelevent but will not be 40 kW.

    You should calculate the heat loss which is likely to be about 12 kW now rising to perhaps 15 kW when you add the extension.

    Even a 35 kW boiler will not supply two high flow outlets at the same time. Its only about 14 litres per minute so thats only 7 li/min each.

    You are likely to need to replace your water supply when you measure the dynamic water flow rate.

    It would be far better to have an unvented cylinder and a proper size boiler!

    Last time I saw a supply request it did have details of the consumption requirements.

    Tony Glazier
     
  4. ianmcd

    ianmcd

    Joined:
    15 Aug 2010
    Messages:
    12,587
    Thanks Received:
    3,743
    Location:
    Lanarkshire
    Country:
    United Kingdom
    Agree with Agile you dont need 40KW for your CH think it might have been 14KW and if you did need 40KW how would you get that out of a 37 KW Boiler ? are you sure your double oven will be gas ? most are fanned electric with gas hob these days, the PE gas supply being inserted into the old service will be 25mm and depends on length from main if this would be suitable but I would be very surprised if it wasnt, your quote from your gas supplier should have a consumption guide on it roughly a U6 meter is capable of supplying 77KW dependant on sufficient supply but this is usually calculated by your supplier
     
  5. Murf520970

    Murf520970

    Joined:
    1 Jan 2011
    Messages:
    2,132
    Thanks Received:
    215
    Location:
    Cheshire
    Country:
    United Kingdom
    if you want to speak to a good quality installer who works your area theres a guy called Dan Robinson who will give you advice .
     
    • Thanks Thanks x 1
  6. Sponsored Links
  7. BGSMJack

    BGSMJack

    Joined:
    2 Nov 2011
    Messages:
    784
    Thanks Received:
    64
    Location:
    Cheshire
    Country:
    United Kingdom
    I think the 22mm pipe you are refering to is infact whats after the meter, rather than before.

    Incoming plastic pipe is, I think 21mm, but the pressure is usally always good. The regulator before the meter then regulates the pressure within the system to ensure that the working pressure at the meter is 21+/- 2mb.

    The pipe work from the meter to the appliance is where your statement is applicable and that is down to your heating engineer to work out if the boiler requires 22mm or 28mm pipework.
     
  8. stardanny

    stardanny

    Joined:
    14 Nov 2007
    Messages:
    1,657
    Thanks Received:
    254
    Location:
    Buckinghamshire
    Country:
    United Kingdom
    How you work that out?

    U6 has a maximum gas rate of 6m3 / heat input 64.62kw/h. Is this correct?

    Dan.
     
  9. ianmcd

    ianmcd

    Joined:
    15 Aug 2010
    Messages:
    12,587
    Thanks Received:
    3,743
    Location:
    Lanarkshire
    Country:
    United Kingdom
    Yes agree with stardanny I was wrong in quoting 77KW approx should have been 66KW approx these are maximum gross but you dont need anything like that, had a blonde moment as have been working on the isle of man where things have to be more accurate in the conversion and 77 KW would be acceptable on an lpg/air mix supply over here, on the mainland U6 meter 6m3 per hour X 11Kwh/m3 = 66kw/h plus the UK conversion factor joke but yes you can get 66KW/h from a u6 if the supply is correct and IT IS 25MM PE not 22mm not 21 mm or anything else,but all else aside you dont need anything like that so go with the previously recommended installer Dan Robinson and you will be fine
     
  10. diyerdude

    diyerdude

    Joined:
    3 Oct 2012
    Messages:
    5
    Thanks Received:
    0
    Location:
    London
    Country:
    United Kingdom
    Thanks all for replies.

    When I called NG they did not mention anything about which supplier I will be using and what size meter they intend to install. There is 'new meter requirements and what size meter is your gas supplier installing' in the form. As NG will be laying the pipe they should be asking these questions. I need to call NG and ask again with the appliance and kw usage.

    ianmcd thanks for clarity for the incoming size of 25mm and U6 flow rate. It seems that it would be sufficient for my usage. I intend to get separate hob and oven and depends on ones preference. It is possible to get both gas - hob and oven, even grill is gas. I don't mind electric but the electric costs are double and slow cooking overall.

    I do intend to change the water pipe as well to 25mm, as I can see a lead pipe to the kitchen.

    As for the CHeating 40kw, vallaint system finder stated 'Your CH power requirement as 40kw'. And it gives two recommendations of boilers -primary recommend of ecoTec exclusive 838 and alternative of exoTec plus837.
     
  11. DIYnot Local

    DIYnot Local

    Joined:
    3 Sep 2019
    Country:
    United Kingdom

    If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

    Select the supplier or trade you require, enter your location to begin your search.


    Are you a trade or supplier? You can create your listing free at DIYnot Local

     
Sponsored Links
Loading...

Share This Page