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

SKU: 484 Series - Type CH 485 Series - Type CHS

Notes: Available in 35°F or 40°F release temperatures.

Product Description

GURU® DL2.1 CH & CHS Product Sheet
GURU® DL2.1 CH & CHS Installation and Maintenance Instructions
GURU® Cap Color Table
Effect of Extreme Cold on the GURU®


  • Will not trip or dump while locomotive is running
  • Fully automatic – it never forgets to activate freeze protection
  • Completely mechanical – No electrical or air connections
  • Not affected by air flow or air temperature surrounding valve – releases only when cooling water reaches setpoint
  • Rapid draining
  • Easy system refill
  • Models available to convert existing freeze protection
  • Easily tested in field
  • Slotted actuator feature prevents nuisance dumps when refilling cooling system with cold water
  • Unit automatically rearms after filling and reheating
  • Optional domed anti-tamper cap eliminates ability to tamper with the valve resetting stemAnti tamper cap


Design Features

  • Easily retrofits into water cooled air compressor heads.
  • Flanged and 2” NPT threaded styles
  • Actuator sensing surface is the only wetted part
  • Long service life: All moving parts are stainless steel
  • Design excludes cooling water chemicals and other debris from moving parts
  • Easy maintenance
  • Paint mask minimizes accidental paint-ins
  • Knob on cartridge for easy installation and removal even in awkward locations
  • Choice of release temperatures: 35°F or 40°F


  • Both are used for water-cooled air compressor head freeze protection.
  • The GURU® CHS adapts to Gardner Denver’s compressor set cooling systems. Most common on EMD’s SD70 locomotives.


The GURU® DL2.1 CH and CHS may be thought of as an automatic freeze-out plug with one important difference: The stainless steel GURU® Cartridge releases itself from its body at a pre-set water temperature (35°F or 40°F), rather than being forced out by the tremendous pressure of expanding ice. This provides almost a full one inch bore to rapidly drain the typical compressor before damage can occur.

Resetting and rearming the GURU® Plug is easily accomplished by simply reheating the cartridge and utilizing our GURU® Flag and Clip or GURU® Flag and Key tool which prevent the GURU® Plug from triggering open again while refilling the cooling system with cold water.