thermomegatech logo



The HAT/RA (reverse-acting heat actuated trap valve) is designed to monitor, control, and regulate flow, utilizing a temperature control actuator to constantly sense in-line fluid temperature. Since it is what we classify as reverse-acting, the valve will open on rising temperatures.

As the fluid temperature increases to within the operating range of the HAT/RA, the thermal actuator modulates the valve open. If the fluid temperature is above the valve’s set point, the valve will continue to modulate open allowing additional fluid discharge.

As the outlet temperature falls, the valve then modulates toward the closed position, reducing flow. This modulating action maintains a relatively constant fluid temperature even as operating conditions vary.


Typical Applications

The HAT/RA valve may be used to regulate the flow of cooling water, glycol or other cooling media in applications requiring economical removal of heat from equipment or a process. Since the HAT/RA valves open on rising temperatures, they can be used in many thermal relief valve applications.


Design Features

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


  • Self-operating – no external power source required
  • Maintains constant discharge temperatures
  • Unaffected by pressure variations
  • Wide choice of set points
  • Operates in any orientation
  • Conserves water



  1. Full open temperatures “XXX” available: 040°F, 045°F, 050°F, 060°F, 070°F, 075°F, 085°F, 095°F, 100°F, 105°F, 110°F, 115°F, 120°F, 125°F, 130°F, 140°F, 150°F, 160°F, 170°F, 175°F, 180°F, 190°F, 200°F, and 210°F
    1. Closing temperature is typically 10°F below the opening temperature
  2. Leak port flow rate specifications:
    1. All 144 Series (B and C-Port) leak flow rates at 60 PSIG (4.1 BAR)
    2. All 145 Series (D-Port) leak flow rates at 40 PSIG (2.8 BAR)
  3. Seal material compatibility:
    1. EPDM – air, water, steam, ketones, and synthetic hydraulic oils
    2. Viton – air, fuel, oil, gas, petroleum-based hydraulic oils
  4. Replace singular “X” with 1 for EPDM body seals; 2 for Viton body seals


  • Sizes: ½”, ¾”
  • Maximum Operating Pressure for B Port: 200 PSIG (13.8 BAR)
  • Maximum Operating Pressure for C Port: 150 PSIG (10.3 BAR)
  • Maximum Operating Pressure for D Port: 70 PSIG (4.8 BAR)
  • Maximum Temperature: 150°F (66°C) over set-point – limit 300°F (149°C)


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

Filter Panel

HAT/RA (reverse-acting heat actuated trap valve)

Sort by
Items per page
View as Grid List
Showing 1-12
Your selection matches 124 results
CENTRO Inc. Line Card
Please take a moment to download and review the CENTRO Inc. line card. By doing so, you will be able to view all the brands and products that CENTRO Inc. distributes and/or represents.