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How to Clean a Steam Radiator Air Valve


Cleaning a Steam Radiator Air Valve or Air Vent
How to Clean a Steam Radiator Air Valve

Old radiator air vents can sometimes get clogged and stuck open.

Steam radiator air vents (or valves) must open and close smoothly for proper operation of a single pipe steam boiler. When the steam boiler is not in a heating cycle, the air vent opens the radiator to room temperature air. During a heating cycle the air in the radiator must be replaced with steam, so the heated steam flows into the radiator and pushes the contained air out. As this occurs, the air vent (actually a heat sensitive valve) will heat up and close, thereby containing the steam in the radiator and preventing it from escaping into the room.

Occasionally the air valve may clog with rust or mineral deposits. Before replacing a troublesome radiator air vent, consider cleaning it to see if you can get it to operate properly. Often the vale just needs a good cleaning as described below:

  • Turn of the steam to the radiator by closing the supply valve (if you have one) found on the end of the radiator opposite the air vent;
  • Using an open-end wrench, remove the valve by turning it in a counter clockwise direction;
  • Heat a small pot of vinegar and place the air valve in the hot vinegar. Allow it to soak for about a half hour, allowing the vinegar to dissolve any mineral deposits and loosen any rust;
  • Rinse the vent with cold water;
  • Test for free air flow by blowing through the valve. If you cannot blow through the air vent then repeat the process again. If you still cannot blow through the valve then it needs to be replaced with a new valve;
  • If you were able to blow air through the valve then replace it into the radiator by wrapping three loops of Teflon tape around the threads in a clockwise manner and replace the air vent (facing upward) until it is hand tight;
  • Reopen the steam supply valve to the radiator and test operation of the valve. The valve should allow air to vent as steam is filling the radiator, and then the valve must close to retain the steam. If the valve does not open and close then the steam radiator air valve needs to be replaced.

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