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

High end Combi vs. Unvented for 3-bed semi-D & 1 bath.

Discussion in 'Plumbing and Central Heating' started by EMFTeo, 18 Jan 2012.

  1. transam

    transam

    Joined:
    20 Nov 2009
    Messages:
    22,988
    Thanks Received:
    2,999
    Location:
    Surrey
    Country:
    United Kingdom
    Have a look at the raven 150 42 kw hot ater out put & adjustable out put for CH !

    u could even fit it with a combi store , for the same money u would pay for other combi's , will give u a certain amount of free hw as well !

    3 year warranty worth a look , may be
     
  2. Sponsored Links
  3. D_Hailsham

    D_Hailsham

    Joined:
    18 Oct 2007
    Messages:
    10,477
    Thanks Received:
    1,322
    Location:
    Kent
    Country:
    United Kingdom
    Presumably you got that from Here.

    It's very misleading as it's the lowest output of one non-combi boiler and the max output of another combi boiler. :rolleyes:

    There are three combi models in the 200W range and the outputs are:

    CH - 5.9 to 23.7; HW - 5.9 to 26; flow rate 10.7 lpm @35C rise
    CH - 7.9 to 27.3; HW - 7.9 to 30; flow rate 12.3 lpm @35C rise
    CH - 7.9 to 31.7; HW - 7.9 to 35; flow rate 14.3 lpm @35C rise
     
  4. EMFTeo

    EMFTeo

    Joined:
    18 Jan 2012
    Messages:
    37
    Thanks Received:
    0
    Location:
    Berkshire
    Country:
    United Kingdom
    Spoke to my plumber again, and he said they were of no match to the 837 on flow rate ?
     
  5. mehran

    mehran

    Joined:
    27 Jan 2007
    Messages:
    3,547
    Thanks Received:
    613
    Location:
    Cleveland
    Country:
    United Kingdom
    a viessmann 200 combi will have at least 4 more moving parts and more parts over all(I could name them if mysteryman would like)

    the only real advice I have for you is the boiler is only part of the equation. a good boiler installed badly will still do badly(integas may put up a better fight but would still lose in the hands of a Muppet)

    so get an installer that you trust and fit the boiler he knows the best.

    if it turns out to be valliant(a spit on the ground emotion) then you will be more likely better of with it.

    btw still think intergas is the best combi boiler in the world :LOL: followed by a close second by atmos(to keep dan happly)
     
  6. Sponsored Links
  7. Dan Robinson

    Dan Robinson

    Joined:
    1 Jul 2007
    Messages:
    56,042
    Thanks Received:
    9,423
    Location:
    Hertfordshire & London
    Country:
    United Kingdom
    :p

    If you are looking at hybrids the the Atmos Multi 24/80+ cocks its leg all over Veissman's offering

    I need to reply to your email so will stick some info in there with some linkies.
     
  8. D_Hailsham

    D_Hailsham

    Joined:
    18 Oct 2007
    Messages:
    10,477
    Thanks Received:
    1,322
    Location:
    Kent
    Country:
    United Kingdom
    The flow rate of the 837 is 15.2 lpm @35C rise. I doubt if any one will notice the difference between that and the 14.3 lpm of the largest Viessmann.

    However, it's not the HW flow rate which is the problem, it's the CH requirement.

    You said your current boiler is 15kW and the online calculator gave 13.25kW. Presumably that is with the house as it is, i.e. without the proposed insulation. If you repeat the calculation, assuming all the proposed insulation, you will find that the requirement has dropped, possibly to as little as 8kW. This would mean that the 837, with a minimum output of 12kW, was massively oversized.

    You cannot select the boiler by considering the HW requirement in isolation, you must take the CH requirement into account.
     
  9. EMFTeo

    EMFTeo

    Joined:
    18 Jan 2012
    Messages:
    37
    Thanks Received:
    0
    Location:
    Berkshire
    Country:
    United Kingdom
    I understand that it's CH which needs to be taken into account then.. our requirements are no more than 15kW for CH and a minimum flow-rate requirement of 13++ lpm ?

    Is there any combi which can supply that?

    Would fitting a multi-fuel/wood burner stove (8kw) in the living room and retrofitting that to a LPG combi or unvented solution work? i.e help minimise LPG consumption in the long run?
     
  10. D_Hailsham

    D_Hailsham

    Joined:
    18 Oct 2007
    Messages:
    10,477
    Thanks Received:
    1,322
    Location:
    Kent
    Country:
    United Kingdom
    Yes, the Remeha Avanta 35C or 39C.

    35C: CH output 6kW to 29kW (the maximum can be reduced by the installer to whatever you like); HW 14.2 lpm @35C rise

    39C: CH output 6kW to 33kW (the maximum can be reduced by the installer to whatever you like); HW 16.9 lpm @35C rise
     
  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