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Thread: Adjusting an ABV and measuring flow rates through the boiler

  1. #11
    Site Sponsor The EVOHOME Shop's Avatar
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    Quote Originally Posted by HenGus View Post
    Then again you could just do what this guy suggests from minute 7.00 onwards:

    https://www.youtube.com/watch?v=KfJ5SrBnoS4
    LOL, well that is the worst ABV I think I have seen installed for a while! Think he needs a heating engineer out, as he seems to have left himself a leak on the pump valve (6:59).

    I personally also use mass flow rate calculation to work heating flow rates out...

    So the flow rate required in kg/second = H/TD*SH (H = heat required in Watts, TD = temperature drop of the system and SH = Specific heat capacity of the fluid (Water = 4187 joules)).

    Pub Question... If a boiler requires a minimum flow rate 1032 litres per hour with a 20 degrees C differential, what is its heat output in kW?

  2. #12
    Automated Home Ninja Dan_Robinson's Avatar
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    Quote Originally Posted by The EVOHOME Shop View Post
    LOL, well that is the worst ABV I think I have seen installed for a while! Think he needs a heating engineer out, as he seems to have left himself a leak on the pump valve (6:59).
    Could be worse... Could be that plumberparts doughnut.

  3. #13
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    Quote Originally Posted by Dan_Robinson View Post
    Could be worse... Could be that plumberparts doughnut.
    I was thinking of you and your shiny pipes when I watch that...

    Output in kW please...

  4. #14
    Automated Home Ninja Dan_Robinson's Avatar
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    24.7kw. Plus some characters to make minimal post requests. :P

  5. #15
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    Quote Originally Posted by Dan_Robinson View Post
    24.7kw
    Correct, 24kW would have been sufficient though... Bet you used your excel spreadshhet for that didn't you...

  6. #16
    Automated Home Legend top brake's Avatar
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    There are several distinct seperate issues to consider here

    The minimum flow through the boiler

    The differential pressure in the radiator circuit

    Whether the pump is modulated according to boiler output or the differential pressure in the system


    That will then determine whether an abv is required and what to adjust it to (if at all)


    Remember the prime reason for fitting an automatic bypass is to prevent system noise as TRVs close
    I work for Resideo, posts are personal and my own views.

  7. #17
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    In my case I need an ABV to maintain a minimum flow rate through the boiler as required in the specs, when all the TRVs close.

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