Open vented system close coupled feed and OSV.

Home Forums Heating System Design Pipe Sizing and Specification Open vented system close coupled feed and OSV.

This topic contains 10 replies, has 4 voices, and was last updated by  jflower 1 year, 9 months ago.

Viewing 11 posts - 1 through 11 (of 11 total)
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  • #649

    jflower
    Participant

    I teach at the RSME, got a colleague who refuses to use the design of close coupled feed and vent to the CIBSE design, saying that he cannot see the reasons behind it, his version works just as well.

    Is he right or CIBSE?

    #650

    Terry Lambert
    Participant

    CIBSE

    There are lots of advantages to a close couple tee configuration, maybe he is not aware of these

    #653

    jflower
    Participant

    It’s not that Terry, in the CIBSE Central Heating Design Guide, they show or used to a close coupled tee arrangement that has a section of 28mm on the 22mm flow a minimum of 150 mm before the OSV tee, this is to reduce the velocity of the water to allow dissolved air to escape up the OSV.

    My colleague places the 28mm between the OSV and the cold feed !!!!!!

    #662

    Andrew Millward
    Participant

    Osv ?

    #663

    alec morrow
    Participant

    I think he means vent pipe…I don’t think the OP (original poster) is talking about CCTS as we talk about them for hydraulic separation

    #678

    Terry Lambert
    Participant

    Ahh open safety vent. OSV

    #679

    Terry Lambert
    Participant

    I miss read the opening post, apologies J Flower

    #680

    Terry Lambert
    Participant

    J Flower

    I havnt seen thiscinfigurwtion before but could see how it would create a Venturi effect. This is interesting, I’ll have to look into this

    #681

    Terry Lambert
    Participant

    So it would create a low pressure zone at the OV helping to expel air

    #683

    Terry Lambert
    Participant

    I should have said high pressure

    #687

    jflower
    Participant

    Because the 28mm causes the velocity of he water to slow down so allowing the air to escape up the open safety vent !

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