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

SKU: 254-000000-XXX

Notes: See product sheet for other seal materials.

Product Description

HST High Sample Temperature Safety Thermal Shutoff Valve

HST Product Sheet
HST Installation and Maintenance Instructions


  • Self-operating – No outside power required
  • Protects expensive and delicate sample analyzers
  • Automatically resets when sample cools
  • Easy installation
  • Superior value vs. more expensive electric valves

Design Features

  • Exclusive self-actuating Thermoloid┬«┬ásensor/controller
  • Ram-type plug provides tight shutoff
  • Operating temperatures unaffected by variable inlet pressures
  • Wide choice of temperature set points available
  • Corrosion resistant – all stainless steel construction


The High Sample Temperature (HST) Safety Thermal Shutoff Valve is used to sense the sample temperature after the sample cooler and control flow based on fluid temperature. This valve is normally open and allows the sample to pass through it. If the sample temperature exceeds the valve set point, the thermal actuator inside the HST will close the valve to protect expensive and delicate analyzers and other instruments from over-temperature damage. Once the fluid cools back below the set point, the valve will automatically reset open again.

Typical Applications

Excessively hot samples can cause damage to expensive and sensitive hardware and electronics. For process analyzers and similar instrumentation, it is important to assure that the process samples fluids are always below the maximum allowable temperature for such instruments. Sample coolers are commonly used to reduce sample temperatures to the acceptable limits. In the event of a loss of cooling fluid to the sample cooler, or if the desired sample temperature is exceeded for any reason, the HST thermal shutoff valve will close to prevent equipment damage.

Low coolant flow, total loss of cooling water, or unusually high sample temperatures are typical reasons why the HST self-operating thermal protection valve should be used.

Typical Install


HST High Sample Temperature Safety Thermal Shutoff Valve