HAT/RA-HP High Pressure Thermal Relief Valve


The self-operating HAT/RA-HP (Heat Actuated Trap/Reverse Acting – High Pressure) Thermostatic Thermal Relief Valve is installed onto the pump to monitor the fluid temperature. If the fluid temperature increases to within the operating range of the HAT/RA-HP, the thermal actuator will modulate the valve open to discharge the over-temperature fluid. As the outlet temperature falls, the valve modulates toward the closed position, reducing flow. This modulating action maintains a relatively constant fluid temperature and reduces wasted water and energy.

Typical Applications

The HAT/RA-HP is commonly used as a thermal relief valve on fire pumps and high-pressure water pumps to keep them cool during idling. It may be used as a regulating valve to maintain the flow of glycol, water, or other media in critical cooling applications and to economically remove heat from equipment or a process.

HATRA-HP - Thermostatic Thermal Relief Valve

Design Features

  • Exclusive self-actuating Thermoloid® wax blend thermal actuator
  • Rated for higher pressure systems – up to 1000 PSIG
  • All stainless-steel body, fittings, spring, and plug
  • Compact, low mass – fast response
  • Corrosion resistant – long service life
  • Ram-type plug for reliable shut-off
  • Operates in a narrow temperature band


  • Self-operating – no external power source required
  • Protects pump and pump seals from over-temperature damage
  • Maintains constant discharge temperature
  • Improves system efficiency
  • Unaffected by pressure variations
  • Discharges minimum amount of water to keep water temperature at safe limits
  • Quick and easy installation
  • NSF/ANSI/CAN 61 & 372 Certified




154 - 010X00 - XXX

1/2” HAT/RA-HP-M/F


  1. Full open temperatures “XXX” available: 090°F, 095°F, 100°F, 105°F, 110°F, 125°F, 130°F, 140°F. – Other temperatures available, consult our product team.
    1. Closing temperature is typically 10°F below the opening temperature.
  2. Replace singular “X” with 1 for EPDM body seals; 2 for Viton body seals.
  3. Seal material compatibility:
    1. EPDM – air, water, steam, ketones, and synthetic hydraulic oils
    2. Viton – air, fuel, oil, gas, and petroleum-based hydraulic oils


  • Size: ½”
  • Maximum Operating Pressure: 1000 PSIG (69 BAR)
  • Maximum Temperature: 250°F (121°C)


HAT/RA-HP Product Sheet
HAT/RA-HP Installation and Maintenance Instructions
Temperature Control Valves For Pumps and Pump Seals Brochure