Price: Contact us for purchase info: (877) 379-8258

SKU: 134 Series (½") 135 Series (¾")

Notes: See product sheet for available sizes and temperatures.

Product Description

HAT Product Sheet
HAT Installation and Maintenance Instructions


  • Controls fluid return temperatures – ideal for glycol tracing
  • Maintains constant discharge temperatures
  • Improves system efficiency
  • Unaffected by pressure variations

Design Features

  • Stainless steel body, fittings, spring, and plug
  • Corrosion resistant – long service life
  • Exclusive Thermoloid® sensor/controller
  • Operates in narrow temperature band
  • Compact low mass – fast response
  • Two wrench flats for easy installation
  • Ram-type plug for reliable shut-off


A thermostatic element inside the valve senses temperature and if this falls below the setpoint, the valve modulates open to allow flow. When the temperature increases to near the setpoint, the HAT (Heat Actuated Trap) valve modulates closed. HAT valves are available with built-in leakage to allow bypass flow.

Typical Applications

  • To control temperatures in glycol heat tracing systems, HAT valves will maintain the discharge temperature. When glycol temperature exceeds the setpoint, the valve will modulate closed. As heat loss occurs and glycol cools to below the setpoint, the valve will open to allow warmer glycol to circulate.
  • HAT valves can act as freeze protection for condensate systems. The valves open when temperatures fall to allow condensate to discharge before freezing.
  • In commercial aircraft, high temperature water can unexpectedly travel to the cold water lines. HAT valves on cold water lines will limit flow when excessive temperatures are detected, preventing scalding of passengers and crew.
  • HAT valves used on tank heating coils limit the temperatures of the heating element. By closing before coil temperatures are too high, the valves reduce the risk of over-temperature damage. When used as a subcooling steam trap, HAT valves reduce problems associated with overheating.
  • When used as a sampling system safety shutoff, HAT valves will remain open as long as sample temperatures are under the setpoint. If the sample temperature increases, the valve will shut off, protecting analyzing equipment from damage due to high temperature.