TP-0357
Revised 06-19
Technical Bulletin
Technical Bulletin
WABCO Inversion
Relay Valve (IR-2)
TP-0357
Revised 06-
19
1 Technical Bulletin
Hazard Alert Messages
Read and observe all Warning and Caution hazard alert messages in
this publication. They provide information that can help prevent
serious personal injury, damage to components, or both.
WARNING
To prevent serious eye injury, always wear safe eye protection
when you perform vehicle maintenance or service.
Park the vehicle on a level surface. Block the wheels to
prevent the vehicle from moving. Support the vehicle with
safety stands. Do not work under a vehicle supported only by
jacks. Jacks can slip and fall over. Serious personal injury and
damage to components can result.
Release all air from the air systems before you remove any
components. Pressurized air can cause serious personal
injury.
Do not attempt to open or disassemble the inversion relay
valve. This valve has an internal spring that may be damaged
by opening the valve. In addition, internal spring forces may
cause serious personal injury.
Overview
Access Product and Service Information
For additional information about WABCO’s inversion relay valve,
please contact the WABCO Customer Care Center at 855-228-
3203. Literature covering the complete WABCO product line is
posted on our website, www.wabco-na.com.
Inversion Relay Valve (IR-2)
The inversion relay valve (IR-2) combines the functions of two air
brake system valves:
앫
A relay valve
앫
An inversion valve with anti-compounding protection
Under normal conditions, the IR-2 responds to a control signal from
a dash-mounted parking brake control valve to supply or exhaust air
from the spring brake chambers, thereby applying the spring
brakes. In the event of a primary air system failure, the IR-2 makes
a modulated application of the spring brakes by means of the foot
valve. A typical IR-2 valve installation is shown in Figure 1.
