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Discuss Radiator TRV 15mm but radiators 22mm?? in the Central Heating Forum area at

  1. bob norfolk

    bob norfolk New Member

    hello, not a problem I’ve thought about before, but having an achp fitted so I need the maximum flow and return volume. However I find I can’t get 22mm TRV/ emitter valves only the standard 15mm. This seems bizarre due to the standard emitter Inlet/ outlet bore size. Will this cause much of a restriction to the low temp system?

  2. Gasmk1

    Gasmk1 GSR

    you can get full bore trvs that are used on single pipe systems if thats what you need
  3. bob norfolk

    bob norfolk New Member

    Thanks. It’s mainly for the increase in pipe sizing due to the air source heat pumps lower temperatures. I’d be interested to know where you can get them as google doesn’t want to know? Cheers
  4. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    What flow rate are the rads you will be less than 15mm I think so the issue will be the rads not the trv
  5. Gasmk1

    Gasmk1 GSR

    Danfoss RA-G15 angled valve 1/2" not cheap and you have to buy the heads as well they dont come complete
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