Refrigerating Specialties Division
7
MODULE OPERATION
MODUDAPTER (Fig. 5)
The Modudapter uses internal flow paths to eliminate
most of the external pilot piping necessary for various
regulator functions. These flow paths serve to connect
the ports in the two mounting Pads 1 and 2 used for
modular pilots.
Flow Path X (Fig. 7) connects directly from Pad 1 to Pad
2 and to the flow Path N from the inlet of the regulator.
Flow Path Y (Fig. 8) connects from Pad 1 to under the
diaphragm.
Flow Path Z (Fig. 9) connects from Pad 2 to top of the
piston.
The Modudapter is used in place of the regular A4A
Adapter for mounting solenoid pilot and pressure pilot
for electric shut-off, electric wide-opening or dual
pressure variations (see Figs. 13 to 18).
A2D MODULAR PRESSURE PILOT (Fig. 10)
This pilot is used in addition to the integral pilot where a
regulator with two pressure settings is required (Fig. 17
and 18 A4AD) and is mounted on Pad 2. Internal
construction shown in Fig. 4.
S6A MODULAR SOLENOID PILOT (Fig. 12)
Depending on the functional requirement, this pilot may
be mounted either on Pad 1 (for A4AS or A4AD) or Pad
2 (for A4AB). See Figures 13 to 18.
Operation-When the solenoid coil is energized, it forms
a magnetic field which pulls the plunger upward striking
the needle and lifting it off its seat. This allows flow
through the solenoid pilot. When the coil is de-energized,
the plunger-needle assembly moves toward the seat and
the needle closes to stop the flow through the pilot.
MODUPLATE (Fig. 11)
This plate is used to direct the flow or stop the flow
through the flow paths in the Modudapter. When mounted
on Pad 2 with the “S” side out, it blocks flow from Path X
to Path Z (see Fig. 13 and 14 A4AS). When mounted on
Pad 1 with the “B” side out, it allows flow from Path X to
Path Y (see Fig. 15 and 16 A4AB).
VARIATIONS-INLET PRESSURE
REGULATORS
These regulators use the Adaptomode modules to
provide electric shut-off, electric wide-opening and dual
pressure variations.
A4AS INLET RESSURE REGULATOR WITH
ELECTRIC SHUT-OFF VARIATION
The A4AS Pressure Regulator controls inlet (evaporator)
pressure when the solenoid pilot is energized and closes
when the solenoid pilot is de-energized, regardless of
the pressure setting or inlet pressure. The S6A Modular
Solenoid Pilot (Fig. 12) is mounted on Pad 1 of the
Modudapter and the Moduplate (Fig. 11) is mounted on
Pad 2 with side “S” exposed. The Moduplate acts to stop
the flow from Path X to Path Z. See Modudapter flow
paths above.
Operation-When the solenoid pilot is electrically
energized, the operation is similar to A4A. The inlet
pressure is transmitted through Passage N to Path X,
through the open solenoid pilot to Path Y. Path Y transmits
the pressure to the underside of the diaphragm (see
Fig. 13) and the pilot will operate as described for A4A
(see page 4). When the solenoid pilot is de-energized,
flow to Path Y is closed and pressure can no longer
reach the area under the diaphragm and the top of the
power piston. This pressure on top of the piston will
equalize through the piston bleed hole and the closing
spring will close the throttling plug, thus shutting off the
flow through the regulator (see Fig. 14).
Adjustment-With the solenoid pilot electr ically
energized, proceed as with the A4A (see page 4).
