Troubleshooting guide

37
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Bendix
®
R-12P
™
Relay Valve
The Bendix
®
RE-6NC
™
(non-charging) relay emer-
gency valve is used in dolly systems and replaces the
conventional RE-6
®
valve. The RE-6NC
™
valve is similar
to the RE-6
®
valve but is designed to prevent direct fi lling
of the dolly reservoir through the RE-6NC
™
valve. It is
generally used in conjunction with the PR-3
™
pressure
protection and single check valve to provide rapid dolly
brake release.
The Bendix
®
PR-3
™
reservoir control valve is the
combination of a Bendix
®
PR-4
™
pressure protection
valve and a single check valve. This valve may be used
in a variety of applications, however the most common is
in the converter dolly brake system — where it functions
to delay fi lling of the reservoir until pressure in the supply
air line exceeds 75 psi — and to prevent pressure loss
due to a failure in the trailer being towed.
The Bendix
®
PP-1
®
control valve is commonly mounted
to the frame and used as a brake release valve. Pushing
in the Bendix PP-1 valve releases the dolly’s parking
brake and allows it to be moved. Since the dolly uses its
own supply air to park, once it’s moved, pulling out the
Bendix PP-1 valve button re-parks the dolly.
Bendix
®
RE-6NC
™
Relay Emergency
Valve
Bendix
®
PR-3
™
Reservoir Control
Valve
Trailer/Converter Dolly Brakes, cont.
Converter Dolly systems also widely use Bendix
®
DC-4
®
double check valves (see page 17),
and Bendix
®
TR-3
™
inversion valves (see page 30).
Bendix
®
PP-1
®
Control Valves
Bendix
®
SV-4
™
Synchro Valve