HAT Fluid Temperature Control Valve


A thermal wax actuator mechanically operates ThermOmegaTech’s self-operating HAT (heat actuated trap) valve. This thermostatic actuator senses the fluid temperature and will modulate the valve open to initiate flow if the temperature falls below the valve’s set point. Once the fluid temperature increases back to the set-point, the valve will modulate closed to control flow. HAT valves are available with built-in leakage to allow bypass flow.

Typical Applications

  • A subcooling steam trap: discharges condensate to an unpressurized outlet, reducing problems associated with overheating.
  • Regulating temperatures in glycol heat tracing: maintains the discharge temperature for glycol heat tracing used for winterization processes.
  • Freeze protection for condensate systems: The heat-actuated trap valves open when temperatures fall to allow condensate to discharge before freezing.
  • High-temperature for commercial aircraft galleys: HAT valves are installed in airplane galleys where manifolds connect coffee makers and faucets to prevent high-temperature water from traveling to the cold-water lines and scalding passengers and/or crew.
  • Regulating temperatures of tank heating coils: HAT valves limit the temperatures of the heating element by closing before coil temperatures are too high to reduce the risk of over-temperature damage.
  • Sampling system safety shut-off: HAT valves will remain open as long as sample temperatures are under the valve’s set-point. If the sample temperature increases, the valve will close, shutting off the flow and protecting analyzing equipment from damage.

Heat Actuated Trap Valve

HAT - Thermostatic Heat Actuated Trap Valve

Design Features

  • Exclusive self-actuating Thermoloid® blend wax thermal actuator
  • Stainless steel body, fittings, spring, and plug
  • Compact, low mass – fast response
  • Corrosion-resistant – long service life
  • Ram-type plug for reliable shut-off
  • Two wrench flats for easy installation
  • Operates in a narrow temperature band
  • Optional leak port (LP) available


  • Self-operating – no external power source is required
  • Return fluid temperature control – ideal for glycol tracing
  • Maintains constant discharge temperatures
  • Improves system efficiency
  • Unaffected by pressure variations
  • Valves with stainless steel internals are NSF/ANSI/CAN 61 & 372 Certified




134 - 302X00 - XXX

1/2” HAT C-Port

134 - 312X00 - XXX

1/2” HAT C-Port, all SS

134 - 502X00 - XXX

1/2” HAT C-RF

134 - 324X20 - XXX

1/2” HAT C-Port, 316 SS Passivated

135 - 502X00 - XXX

3/4” HAT D-Port

135 - 512X00 - XXX

3/4” HAT D-Port, all SS


  1. Flow direction is reversed in valves that close over 210°F (98.9°C). Reverse flow valves are rated for 150 PSIG (10.3 BAR)
  2. Seal Material compatibility:
    1. EPDM – air, glycol, water, steam, ketones, and synthetic hydraulic oils
    2. Viton – air, fuel, oil, gas, petroleum-based hydraulic oils
    3. Kalrez
    4. Silicone
  3. Full open temperatures “XXX” available: 040°F, 050°F, 055°F, 060°F, 065°F, 075°F, 085°F, 090°F, 095°F, 100°F, 105°F, 110°F, 120°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 the opening temperature.
  4. Replace singular “X” with 1 for EPDM body seals; 2 for Viton body seals. For other seal options or leak port designs consult our product team.


  • Sizes: ½”, ¾”
  • Maximum Operating Pressure: 300 PSIG (20.7 BAR)
  • Maximum Temperature: 150ºF (66ºC) over set-point limit 300ºF (149ºC)


HAT Product Sheet
HAT Installation and Maintenance Instructions
Instrument and Process Temperature Control Brochure