Rail Compressor Freeze Protection Overview
The GURU® CH and CHS valves retrofit into the compressor head and use ThermOmegaTech’s self-actuating Thermoloid® thermal actuator to provide automatic freeze protection.
While circulating coolant remains above the valve’s release temperature, the cartridge stays closed to prevent unnecessary draining during locomotive operation. The cartridge design supports easy system refill and allows the CH and CHS valves to be maintained and tested in the field.
Design Features
- Exclusive Thermoloid® paraffin wax actuator is the only wetted part, allowing the valve to respond directly to cooling water temperature
- Slotted actuator feature prevents nuisance dumps when refilling the cooling system with cold water
- Design excludes cooling water chemicals and other debris from moving parts
- Paint mask minimizes accidental paint-ins during locomotive service
- A cartridge knob supports installation and removal in restricted locations
- All moving parts are stainless steel
- Optional domed anti-tamper cap eliminates the ability to tamper with the valve resetting stem
Locomotive Compressor Head Applications
The GURU® CH and GURU® CHS valves provide water-cooled compressor head freeze protection for diesel locomotive air compressor systems. The CHS configuration is designed for Gardner Denver compressor set cooling systems commonly used on EMD SD70 locomotives.
Maintenance & Rebuild Support
ThermOmegaTech® offers a Rebuild Program to support ongoing maintenance of GURU® CH and CHS rail freeze protection valves and help keep fleet equipment in service.
GURU® Rebuild ProgramGURU® CH and CHS Resources
Product Literature
Specification & Installation
Additional Resources
Technical Specifications
- GURU® CH Valve Connection: Flange
- GURU® CHS Valve Connection: 2” NPT
- Release Temperatures: 35°F (1.7°C) or 40°F (4.44°C)
Ordering
| PART NUMBER | DESCRIPTION |
|---|---|
| 481-04-82-CART | 35°F RELEASE DL2.1 TYPE CARTRIDGE ONLY |
| 481-04-81V-CART | 40°F RELEASE DL2.1 TYPE CARTRIDGE ONLY |
| 484-04-88 | 35°F RELEASE DL2.1 TYPE CH |
| 484-04-84 | 40°F RELEASE DL2.1 TYPE CH |
| 485-04-88 | 35°F RELEASE DL2.1 TYPE CHS |
| 485-04-87 | 40°F RELEASE DL2.1 TYPE CHS |
| 475-010110-035 | 35°F RELEASE CARTRIDGE ONLY ANTI-TAMPER CAP |
| 475-010010-040 | 40°F RELEASE CARTRIDGE ONLY ANTI-TAMPER CAP |
| 475-006110-035 | 35°F RELEASE DL2.1 TYPE-CH ANTI-TAMPER CAP |
| 475-006010-040 | 40°F RELEASE DL2.1 TYPE-CH ANTI-TAMPER CAP |
| 475-007110-035 | 35°F RELEASE DL2.1 TYPE-CHS ANTI-TAMPER CAP |
| 475-007010-040 | 40°F RELEASE DL2.1 TYPE-CHS ANTI-TAMPER CAP |
How the GURU® CH and CHS Valves Operate
The GURU® DL2.1 CH and CHS sense cooling water temperature at the locomotive air compressor head. When water reaches the specified 35°F or 40°F release temperature, the cartridge releases from the valve body to rapidly drain water from the compressor head cooling passages before freeze damage occurs.
Resetting and Refilling
After activation, the cartridge is reheated and reinserted into the valve body. During system refill, the GURU® Flag and Clip or GURU® Flag and Key can be used to prevent cold refill water from prematurely releasing the cartridge. Once the system is filled and reheated, the valve automatically rearms.
