MultiTherm 660® Heat Transfer Fluid

Heat Transfer Fluid for Closed–Loop Heat Transfer Fluid Systems

Heat Transfer Fluid 
MultiTherm 660® is a uniquely engineered high-temperature synthetic heat transfer fluid used in non-pressurized / low-pressure liquid phase heating and cooling systems up to 660°F / 349°C.

MultiTherm 660® heat transfer fluid is highly engineered to provide fluid stability and long life. In the Gas Processing it is used in dehydrators, NGL reboilers as well as process equipment, in the Chemical Process to heat & cool reactors as well in heat recovery systems. Biodiesel Production benefits by being able to run at higher temperature in the distillation process and in Plastic Processing to provide consistent heat to molds or dies as well as laminating lines. This is just to name a few.

MultiTherm 660® heat transfer fluid is designed with a maximum film temperature of 710°F / 377°C, autoignition point of 810°F / 432°C and a maximum operating bulk temperature of 660°F / 349°C to provide users with a safe, durable & economical heat transfer fluid over other conventional thermal fluids.

Closed Loop Systems
MultiTherm 660® is designed for use in liquid-phase heat transfer systems, which the circulating loop is “closed” to the atmosphere. To maximize the product’s superior thermal stability, it is recommended that the system have inert gas blanketing the expansion tank. This will guard against exposure to air and water which will minimize oxidative degradation and maximize fluid life.

Physical Properties
MultiTherm 660® heat transfer fluid provides outstanding thermal and oxidative stability to the end user with reduced volatility, significantly higher autoignition temperature and lower pumpability. MultiTherm 660® is pumpable down to 13°F / 11°C and has a maximum bulk oo temperature of 660 F / 349 C. This wide temperature range combined with optimal performance and efficiency benefits a majority of liquid phase applications. If the fluid is ran at the maximum bulk temperature, it is recommend to also utilize a filtration system to remove the particulate caused by thermal cracking during start-ups & shut-downs or when there is a loss of power to the system. MultiTherm 660® is non-corrosive to metals commonly used in the design of heat transfer systems.

Benefits of MultiTherm 660®

  • Excellent Thermal Conductivity at high temperatures
  • Resists Thermal Breakdown in closed–loop systems
  • Long Service Life
  • Excellent performance
  • Low Pumpability Temperature
  • High Autoignition Temperature
  • Maximum Bulk Temperature up to 660°F / 349°C
  • Low Vapor Pressure
  • Non-Corrosive
MultiTherm 660® Physical Characteristics*
Chemical Type Synthetic Alkylate
Appearance Clear Liquid
Odor Virtually Odorless
Pour Point, ASTM D97 -44°F / -42°C
Density @ 60°F/15°C

8.0 lb/gal
959 kg/m3

Flash Point, coc, ASTM D92 >360°F / >182°C
Fire Point, coc, ASTM D92 >420°F / >216°C
Autoignition Point, ASTM E659 >810°F / >432°C
Atmospheric Boiling Point (10%) >565°F / >296°C
Kinematic Viscosity, at 40°C 11.9 cSt
Kinematic Viscosity, at 100°C 2.44 cSt
Maximum Film Temperature 710°F / 377°C
Maximum Recommended Bulk Temperature 660°F / 349°C
Molecular Weight 245
Pumpability Temperature @ 300 cPs 13°F / 11°C

*Typical properties, not specifications


Warranty: MultiTherm® warrants that MultiTherm 660® conforms to the data set forth in this brochure. We present this information in good faith, but because we cannot control or anticipate the many different conditions under which our information and product may be used, no other warranty, expressed or implied, is given.