Maid-O’-Mist® manufactures and markets automatic and manual air elimination valves for hydronic, steam and solar applications. We also manufacture and market a line of float operated level controls for water applications.

Since 1932, Maid-O’-Mist® has been manufacturing the most complete line of air elimination valves in the industry. We offer fifteen models of air elimination valves, twenty models of steam valves and seven models of vertical/horizontal float operated water level controls to meet your hydronic, steam, solar and water application needs.

Automatic Air Valves

Correct 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.


The Maid O Mist Replacement Thermocouples are for gas furnaces, boilers and water heaters that operate on 30 millivolt systems. Our thermocouples sense the pilot flame on standing pilot gas-fired heating systems. The pilot flame heats the tip of the thermocouple, producing a temperature differential between it and the base to generate 30 millivolts.

Float Control Valves

High Capacity Forged Brass Vents

Purges and eliminates air in water lines, installs vertical at highest points on line.

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.

Manual Vents

Shutoffs and Connectors

Vertical Radiator Steam Vents

Tankless Water Heater Connection Valves

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