Rads dont get hot with mono valves

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by sprinkler, Dec 13, 2007.

  1. sprinkler

    sprinkler New Member

    Messages:
    72
    I have added a few new rads to my home heating system and 3 of them don't get hot. These 3 rads have new mono type valves (which means the flow and return are together connecting to one side of the rad).

    Both flow and return pipes are hot going into the valve, but it seems the water just goes in the flow pipe and out the retrurn pipe without actually heating the rad.

    Could it be that the shop forgot to give me a short piece of plastic tube which forces the hot water some distance inside the rad? And without this tube the hot water doesnt get inside the rad? Because I remember fitting similar valves before, but they came with a short piece of tube, about 10 cm long.
    Thanks.
  2. cwhyu2

    cwhyu2 Consultant

    Messages:
    1,348
    Location:
    Cincinnati OH
    Are there bleeder valves at the top of rad,if so you may have to bleed
    the rads of air.
  3. sprinkler

    sprinkler New Member

    Messages:
    72
    I have spent ages bleeding the 3 rads individually. While Im bleeding they do get hot , but when I finish, they just return to normal, almost cold.

    But my main question is: should this type of mono valve (Giacomini) come with a short piece of`plastic pipe to make the hot water actually get inside the rad? Thats the only thing I can think of because other mono valves I had installed before came with a short piece of plastic tube.
  4. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,304
    Location:
    Cave Creek, Arizona
    rads

    Without something to divert/direct the flow the water will just enter the radiator and then exit immediately out the return line.
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