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Discuss PRV combinations to tundish in the Central Heating Forum area at

  1. Lofty24

    Lofty24 Member

    I'm fitting a system that requires 4 T/PRV's I know that i can combing two into the same D1 pipe as long as the D2 is large enough to carry the flow can I combine more than two in to the same D1 or D2 to take it to the drain.

  2. ShaunCorbs

    ShaunCorbs Trusted Plumber GSR Top Contributor!!

    TBH I would

    Each prv has its own run dish and join them all all up after d2

    E.g. If they were all in line and close to each other main drain line in 35-42mm (depending on distance) and t off in 22mm to each of them

    Hope that makes sense
    • Like Like x 1
  3. Lofty24

    Lofty24 Member

    Nice one Thank you.
  4. Francis.

    Francis. Engineer

    I would also consider . What's the chances of more than one prv ever blowing off at the same time... It can be quite difficult to keep the routing tidy..
    The regs show a tee can be in the line before a Tundish..
    • Like Like x 1
  5. Lofty24

    Lofty24 Member

    All PRV's that came with the system are at different ratings so not all are going to pop at the same time, two on the domestic water, one cold in and one hot out, one on the underfloor heating and one on the ground source flow so three systems 4 valves.
    I think Two and Two teed on the D1 with the 500mm min to the tundish then two D2's to the waste.

    Thank you
  6. AWheating

    AWheating Trusted Plumber GSR

    I would follow installation instructions. If they show 2 joined like most do then only join 2 together. If they don't show any info stick to regs and up size as any are joined.
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