Bulletin 22-05 A / Page 5
Manual Opening Stem
Th
ese valves are equipped with a
pressure driven manual opening
system versus the mechanical screw
thread mechanism. A small valve is
opened that allows the inlet pressure
trapped above the piston to escape
via passage (M), through the port plug
and into passage (T), the valve outlet.
top of the piston. Th
e top and bottom
pressure on the piston equalizes and
the weight of the piston along with the
closing spring force prevents the valve
from regulating.
Note:
when the ‘S’ feature solenoid
is de-energized the piston remains
closed regardless of the outlet
pressure. Simply energize the ‘S’
feature on the valve to regulate.
A4WOBS Principle of Operation
Th
e port plate for the A4WOBS is the
same port plate used for the A4WOB
and A4WOS. Th
e regulating portion
of the valve works in the same manner
as the A4WOS described earlier. Th
e
A4WOBS principle of operation cross-
section shows the ‘B’ and ‘S’ solenoid
features. When both solenoids are
de-energized, there is no fl ow from
the top of the piston and therefore
the pressure on top of the piston is
equalized to that on the bottom, inlet
pressure, through the bleed hole and
the valve is closed due to the weight
of the piston in combination with the
closing spring. When the ‘S’ solenoid
is energized it allows the valve to
regulate. When the ‘B’ solenoid is
energized it overrides the ‘S’ feature
and the valve will is fully open.
Note:
for more details on the
principles of operation for the ‘B’ and
‘S’ features see the previous single
operations.
A4WOK and A4WOBK Principle of
Operation
Th
e A4WOK and A4WOBK operate in
the same manner as the A4WO and
A4WOB. Th
ese regulators are factory
set for a given set pressure. Th
e seal
cap is wired to the bonnet cap screw
and the wires are sealed with a lead
seal. Th
e relief pressure setting is
stamped on the seal.
Note:
if the lead seal is removed from
the ‘K’ featured valves prior to one
year of installation the warranty is
voided.
A4WOE and A4WOES Principles of
Operation
Th
e A4WOE and A4WOES version
of the outlet regulator has a remote
sensing connection, which allows
A4WO Manual Opening Stem Cross Section
Installation
All regulators are packed for a
maximum protection. Unpack
carefully. Check the carton to make
sure all items are unpacked. Save the
Passage
Description
T
Outlet Pressure
M
Manual Opening Stem
Th
e small valve stem is located on the
side of the port plate as shown in the
A4WO manual opening stem cross-
section diagram. Using a screw driver,
turn the CCW to manually open the
valve. Turn the stem CW to put the
valve back into automatic operation.
Th
ere must be at least a 2 psi pressure
drop across the valve to completely
open the valve. If there is less than
a 2 psi pressure diff erence available
the valve will be partially open and at
some point less than 2 psi will close.
Th
ere is still a leak path between the
valve inlet and outlet through the
manual opening valve for pump down
purposes.
T
M
Manual
Bypass
Stem
Manual Opening
Stem in Closed
Position:
Manual Opening
Stem in Open
Position:
T
M
Manual
Bypass
Stem
control of downstream pressure at a
point remote from the regulator outlet.
Th
e port plate gasket (#35) has no
hole, thus blocking fl ow of upstream
pressure to the under side of the
diaphragm. Th
e sensing pressure from
the desired control point, downstream
of the regulator, is connected to the
gauge port (#26). Th
us the regulator
will control the pressure at the sensing
point. Th
e regulator operation and
adjustment is the same as the A4WO
and A4WOS.
