BENDIX DV-2 User Manual

®

Bendix® DV-2™ Automatic Reservoir Drain Valve

SD-03-2501

BODY

SEALING

RING

VALVE

GUIDE

ELECTRICAL

LEAD WIRE

STANDARD DV-2

VALVE

™

ADAPTER

WIRE STEM

DV-2™ VALVE WITH HEATER AND THERMOSTAT

DV-2™ VALVE WITH

HEATER

RESERVOIR

EXHAUST

PORT

TOP

PORT

SIDE

RESERVOIR

PORT

INLET &

EXHAUST

VALVE

HEATER ELEMENT

COVER

THERMOSTAT

HOUSING

DESCRIPTION

The DV-2™ automatic reservoir drain valve ejects moisture
and contaminants from the reservoir in which it is connected.
It operates automatically and requires no manual assistance
or control lines from other sources.

The automatic reservoir drain valve has a die cast aluminum
body and cover and is normally mounted either in the bottom
of the reservoir using the top port of the drain valve or in the
end of an end drain reservoir using the side port of the valve.

The DV-2™ valve is also available with a heater and thermostat
cast into the cover for vehicles operated in subfreezing
temperatures. The heated DV-2™ valve is supplied in either
a 12 or 24 volt model and in bottom or end drain configuration.
A 1/4" male pipe adapter is supplied with all DV-2™ drain
valves, end drain and bottom drain, both standard and heated.
This adapter should be installed directly into the reservoir.
Early versions included a filter screen in the adapter. The
filter should be discarded. Later versions may have a standard
pipe nipple instead of the adapter.

1

NOTE: If a vehicle equipped with a DV-2™ automatic drain

valve(s) is operated in subfreezing temperatures, it
is recommended that a heated reservoir drain valve
is installed.

OPERATION

Referring to Figure 1, with no air pressure in the system, the
inlet and exhaust valves are closed. Upon charging the
system, a slight pressure opens the inlet valve (Figure 2)
which permits air and contaminants to collect in the sump.
The inlet valve remains open when pressure is ascending in
the system until maximum (governor cutout) pressure is
reached. The spring action of the valve guide in the sump
cavity closes the inlet valve. The inlet valve and the exhaust
valve are now closed (Figure 3).

Manual draining can be accomplished as follows:
Using a tool, move the wire in the exhaust port upward,

holding it in until draining is completed.

™

The thermostat on the heated model DV-2

automatic drain
valve will activate the heating element when the valve body
reaches a temperature of approximately 45°F and will
deactivate the heating element when the valve body is
warmed to approximately 85°F .

PREVENTIVE MAINTENANCE

Important: Review the Bendix Warranty Policy before

performing any intrusive maintenance procedures. A warranty
may be voided if intrusive maintenance is performed during
the warranty period.

When reservoir pressure drops slightly (approximately 2 psi),
air pressure in the sump cavity opens the exhaust valve
(Figure 4) and allows moisture and contaminants to be
ejected from the sump cavity until pressure in the sump
cavity drops sufficiently to close the exhaust valve.

The length of time the exhaust valve remains open and the
amount of moisture and contaminants ejected depends upon
the sump pressure and the reservoir pressure drop that
occurs each time air is used from the system.

No two vehicles operate under identical conditions, as a
result, maintenance intervals may vary. Experience is a
valuable guide in determining the best maintenance interval
for air brake system components. At a minimum, the
automatic reservoir drain valve should be inspected every 6
months or 1500 operating hours, whichever comes first, for
proper operation. Should the automatic reservoir drain valve
not meet the elements of the operational tests noted in this
document, further investigation and service of the valve may
be required.

FIGURE 1 FIGURE 2

FIGURE 3 FIGURE 4

2