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Maid-O’-Mist Products

Mason-Dallas is proud to offer MaidOMist products. MaidOMist manufactures automatic and manual air elimination valves for hydronic, steam and solar applications and float operated level controls for water applications.

Automatic Air Valves. For All Hot Water and Solar Heating SystemsCorrect problems and avoid trouble by installing these float-operated Auto-Vents. They vent air from mains, solar panels, pipe lines, boilers, unit heaters, chillers, convectors, radiant panels, coils, baseboard and free-standing radiation.

Jacobus® Steam Vents. A vent port size for every room, from the largest size for the coldest rooms to the smallest size for the “too hot” rooms.. Easy to install on any radiator.


  • 16 Different Models
  • Self-Adjusting Thermostatic Control
  • Float to Prevent Water Escape
  • Reduces Radiator Noise
  • Cuts Fuel Consumption
  • Assures Even Heat Distribution
  • Lowers Operating Costs

Vertical Radiator Steam Vents. Single-port, straight-shank vent for small steam systems. Angle cut of telescopic siphon assures positive drainage.


  • Size Connection: 41 1/8″ Straight shank
  •       43 1/4″ Straight shank
  •       45 1/2″ Female x 3/4″ male straight shank
  • Maximum Pressure: 10 PSI

    Auto Vent 670. Maid-O’-Mist’s new No. 670 forged brass Auto-Vent is an ideal automatic vent for hydronic heating applications. With the highest capacity rating available for a forged air vent in the 35-50 psi range, a No. 670 Auto-Vent will relieve air much faster than any comparable automatic vent.

    Auto Vent 675. The Auto-Vent 675 purges and eliminates air in water lines, installs vertical at highest points on line. A low cost, low profile vent valve made of forged brass with a Polypropylene float with a 1/8 NPT connection – Great for places where height restrictions are an issue! “Only 1 ½ inches in height.


    Mason-Dallas, Inc
    2131 Regal Parkway
    Euless TX 76040 US


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