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one radiator stays cold

helium Member Posts: 8
i have new vents from fw webb on my radiators. all of a sudden one stays cold, while others get super hot.


  • al leone
    al leone Member Posts: 25
    cold rad

    check service valve for full open position, It has to be fully oped or fully closed if rad is not in use, It should never be used to control heat.
    Sometimes an old air-vent can cause water to biuld up in radiator. Try pitching the rad, lift the back legs and put some plywood under them or a couple of plastic checkers.
    Water has to drip back to the boiler when rad cools off,
    If the new vent is venting too fast it can cause consensation inside a big radiator
    Can you disconnect the rad and check inside for water or blockage?
  • Dale
    Dale Member Posts: 1,317

    As the other post suggested make sure the valve on the cold rad is wide open. Then unscrew the new vent and see if the cold rad heats, process of elimination. If vent out and valve open and no steam take valve apart, watch for smelly water. Sometimes if someone overfilled a boiler suddenly gunk gets stuck and blocks lines. Hope for a bad new vent or closed valve.
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