Running a combi boiler along with tankless gas water heater

Discussion in 'Plumbing and Central Heating' started by Nikki Mikki, 24 May 2021.

  1. Nikki Mikki

    Nikki Mikki

    Joined:
    24 May 2021
    Messages:
    1
    Thanks Received:
    0
    Country:
    United Kingdom
    Hi everyone,

    We are currently doing a loft conversion and rear extension which will give us 3 bathrooms (3 showers 1 bath). It is very unlikely that we will ever end up using all 3 simultaneously but there is the possibility for 2 showers at once at some point. I must add that the CH will be replaced with UFH throughout the house. The house is 4 bed mid terraced. We currently have a combi Vaillant green iq843 which is about 3 years old and although is one of the biggest available on the market the builder is adamant that it won't be sufficient for 2 showers hence he recommends adding 210l Megaflo to the combi. Our main concern with the Megaflo is the size of the cylinder and after some research, we discovered Rinnai water heaters, especially the N1600i model capable of delivering 35l/min. The general idea is the UFH, kitchen and ground floor shower to be fed via the combi whilst the other 2 bathrooms to be fed through the Rinnai water heater. Have any of you considered a tankless water heater over a Megaflo and if so do you see any limitations in this arrangement? Many thanks in advance!
     
  2. Sponsored Links
  3. ianmcd

    ianmcd

    Joined:
    15 Aug 2010
    Messages:
    23,972
    Thanks Received:
    10,074
    Location:
    Livingston
    Country:
    United Kingdom
    Not that simple, all depends on your gas supply very unlikely your supply will be big enough for both
     
  4. muggles

    muggles

    Joined:
    28 Oct 2005
    Messages:
    13,427
    Thanks Received:
    3,104
    Location:
    Daventry
    Country:
    United Kingdom
    The Vaillant is 43kW, the Rinnai is 58.4 kW, total 101.4kW. The maximum you can pull through a standard domestic U6 gas meter is 65kW, so you'd need to get an upgrade to a large domestic U16 meter, which is about the size of a washing machine by the time the enclosure is installed around it as well. You'd also need to engage a commercial gas engineer as the domestic engineer's limit is 70kW.

    Have you had your incoming mains tested to see what it can actually deliver? There's absolutely no point putting a water heater in which can deliver 35l/min if your incoming mains is only providing 25l/min, for example
     
    • Like Like x 1
  5. 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

     
Loading...

Share This Page