Troubleshooting guide

26
www.bendix.com 1-800-AIR-BRAKE (1-800-247-2725)
Lever Operated Control Valves
Dual Function Quick Release Valve
The QR-1C
™
valve has a dual function. It works as a
quick release valve for rapid park brake actuation and
also provides anti-compounding, since its double check
valve prevents simultaneous service and emergency
spring brake applications.
Relay Valve
QR-1C
™
Quick
Release
Valve
QR-1C
™
Quick
Release Valve
Lever Operated Control Valves
The TW-2
™
and TH-3
™
valves are identical in
appearance (and similar to the TW-1
™
, TW-3
™
and
TW-4
™
) except they have two control valves housed
in a single body. These two valves differ by the internal
cammed control lever, which for the TW-2
™
control
valve has two lever positions, while the TH-3
™
valve
has three.
The TW-1
™
, TW-3
™
and TW-6
™
series control valves
are manually operated, non-modulating (on - off)
control valves used in a wide variety of control
functions. The TW-1
™
and TW-3
™
are dash-mounted,
lever-controlled valves.
The TW-4
™
is a manually operated momentary non-
modulating control valve commonly used in conjunction
with air starter systems.
A momentary push-type control valve, the TW-5
™
will
deliver air pressure when the plunger is pushed in and
exhaust delivered air when the plunger load is released.
A typical application is for control of a differential lock-
out.
Stop Lamp Switches
The SL-4
™
and SL-5
™
stop lamp switches are pressure-
sensitive electro-pneumatic switches installed in the
service application system. They operate the vehicle
stop lamps by completing an electrical circuit and
lighting the stop lamps each time a brake application is
made.
See page 14 for the DS-2
™
double check and stop light
switch.
TW-1
™
Valve
TW-2
™
,
TH-3
™
Valve
TW-3
™
Valve
SL-5
™
Switch
TW-11
™
Valve