The US/A (Ultra Steam Control – Ambient Sensing) valve, will open or close over a 10°F (5.5°C) differential (i.e. 35-45°F, 90-100°F, etc.) to control the flow of steam, gas, or fluid through the valve to protect piping and instrumentation from freeze damage.

These self-actuating valves are normally closed and will begin to open to inject steam or another fluid when the ambient temperature drops below the valves’ set-point. The valves will close again once the air temperature rises back above the valves’ set-point, saving thousands of dollars in wasted operating costs (Example, a 35°F valve would open at 35°F to turn on the flow of steam and then close at 45°F).

Typical Applications


There are many uses for these compact, self-contained, automatic flow control valves. The most common applications include automation of winterization steam tracing lines, control of pneumatically operated pumps for injection of anti-freeze liquids, and water line freeze protection.

These steam tracing control valves are also ideal for controlling steam heated drum heater enclosures and plate or panel coil tank heaters.

In cooling applications, the reverse-acting US/AR can be used to automate cooling sprinklers, cooling baths, and more.

Design Features

  • Exclusive self-actuating Thermoloid® blend wax thermal actuator
  • Stainless-steel body, fittings, and plugs
  • Compact, low mass – fast response
  • Corrosion-resistant – long service life
  • Ram-type plug for tight reliable shutoff
  • Operating temperatures unaffected by pressure
  • Wide choice of set-points available


  • Self-operating – No external power source required
  • Reduces winterization maintenance and labor procedures and costs
  • Efficiently automates steam tracing
  • Eliminates wasted steam
  • Quick and easy installation




614 - 000100 - XXX

½” US/A

615 - 000100 - XXX

¾” US/A


  1. Full open temperatures “XXX” available: 035°F, 040°F, 050°F, 055°F, 060°F, 065°F, 075°F, 085°F, 090°F, 095°F, 100°F, 105°F, 110°F, 125°F, 130°F, 140°F, 150°F, 155°F, 160°F, 170°F, 180°F, 190°F, and 200°F
    1. Closing temperature is typically 10°F above opening temperature for Direct Acting valves


  • Sizes: ½”, ¾”
  • Maximum Operating Pressure: 200 PSIG (13.8 BAR)
  • Maximum Valve End Temperature: 388°F (198°C)
  • Maximum Sensing End Temperature: 250°F (121°C)


US/A Valve Product Sheet
US/A Installation and Maintenance Instructions
Instrument and Process Temperature Control Brochure