14
Figure 12a. Flow Conditions
Pressure to ‘‘B’’ - ‘‘A’’ to Tank
Figure 12b. Flow Conditions
Pressure to ‘‘A’’ - ‘‘B’’ to Tank
Figure 12c. Flow Conditions
Flow Blocked (Center Condition #2 Spool)
CAUTION
DO NOT energize both (AC) solenoids
simultaneously. Sustained operation with both
solenoids energized will cause excessive
current in the coil and accelerates burnout.
A. Electrical Solenoid Types Available: Three basic
types of electrical solenoids exist: Wet armature, air gap and
high performance. The unit nameplate identifies the type of
solenoid being used. See the model code in Table 2. If a 50
or 51 design two stage valve is equipped with a DG4V-3 pilot
valve, the letter ‘‘M’’ is stamped into the nameplate (i.e.
DG5V-062*-*M-51). The letter ‘‘M’’ indicates an adapter plate
is used to provide the necessary DG4V-3 pilot valve
interface requirements.
B. Wet Armature Type Solenoids: Wet armature
solenoids are standard on DG4V-3, DG4S4-01-60, and
DG4V4-01 pilot valves only. Wet armature solenoids have
many design advantages over other types of solenoids.
Some advantages include cooler operation, static sealing
arrangements, immunity to moisture and greater burn-out
resistance.DG4V-3 and DG4S4-01* wet armature solenoids
are not serviced with individual parts. Service is provided by
replacing the entire core tube subassembly. Parts can be
removed, cleaned and seals replaced on ‘‘W3’’ type
solenoids.
C. Air Gap Solenoids: DG4S4-01 pilot valves are usually
equipped with air gap solenoids. Air gap solenoids are isolated
from system fluid and can be removed and replaced without
disturbing the system. A push pin and sliding seal couple the
solenoid to the valve spool (see Figures 13a and 13b).
E. Electrical Solenoid Voltage Requirement: Electrical
solenoids are available in various AC and DC voltage
ranges. The standard voltage and frequency range is 115V
AC, 60 Hz. Refer to parts and service drawings for units with
non-standard voltage ranges. Fifty (-50) and fifty-one (-51)
design units have the voltage and frequency range stamped
into the nameplate if other than standard. Ten (-10), twenty
(-20) and fifty-three (-53) design units use an identification
letter for the coil voltage and frequency.
F. Electrical Solenoid Ground Connections and Wiring
Housing: An electrical wiring housing with a
1
/
2
” NPTF
thread connection is available on DG4V-3 and DG4S4-01
pilot valves. the wiring housing can be rotated 180
from the
position shown in Figure 13a. Wire grounding screws are
provided for convenience.
Figure 13a. Typical DG4V-3(S)-A/B-FW-60
Terminal Box
Flying Lead
Coil
Manual Override Plunger
Wet Armature (Standard)
Push Pin
Core Tube
Solenoid
Coil
Pilot Spool
Body
G. Manual Override: each solenoid (electrical or air type)
has a manual override plunger to shift the pilot spool. This
feature allows a technician to shift the pilot spool when
electricity or air pressure is not available. Refer to Figures
13a or 13b. To operate the manual override feature, obtain a
small rod and push in on the plunger.
