Brochure

Catalog CIC-2003-1/US
Parker Hannifin Corporation
Climate & Industrial Controls Group
Cleveland, OH
355
Industrial Refrigeration Products: Pressure Regulators
Industrial
Refrigeration
Products
Application Guide
There are many possible combinations of A4 regulator variations. The electric shut-off (S), electric wide-opening (B) and
dual pressure (D) variations are often combined with each other. Or they may be used in combination with the compensated
(M, P, 3P and T), outlet pressure (O) or differential pressure (L) regulators. Remote configurations of most variations are
available using the A4R regulator separate from pilot controls.
A4 Adaptomode
®
Series
The most common variations of the Type A4 regulator appear on the
following pages. For other combinations, please consult Parker.
Variation
Type
Type Function Operation Typical Applications
Suffix
Basic regulator —
Electric shut-off S
Electric wide opening B
Dual Pressure D
Reseating relief K
Outlet pressure
regulator O
Differential pressure
regulator L
Electrically
compensated M
Pneumatically
compensated P, 3P
Temperature T
operated
Electronic pilot
operated J
Externally equalized E
Main regulator for
R
remote pilot
Basic regulator
Z
assembly
Control inlet pressure
Control inlet pressure
or shut off regulator
Control inlet pressure
or wide open
regulator
Dual pressure control
Reseating relief
regulator
Control outlet
pressure
Control pressure
difference across
regulator
Motor changes
pressure set-point
Air pressure changes
set-point (1:1 ratio);
A4A3P for 3:1 ratio
Temperature bulb
controls regulator
opening
Electronic signal
controls regulator
opening
Control at external
pressure sensed
remote from valve
Main regulator is
controlled by
separate pilots
Complete regulator
assembly to which
modules can be
added.
Operates at present inlet pressure.
Can be field adjusted. Opens on
rising inlet pressure.
Regulates when electrically
energized; closed when not
energized.
Regulates when not electrically
energized; wide open when
energized.
Regulates at lower pressure
when electrically energized; at
higher pressure when not ener-
gized.
Open wide above set point.
Repeatedly reseats after
operation.
Regulates at preset outlet
pressure.Can be field adjusted.
Opens on a drop in outlet pressure.
Regulates pressure difference at
or below a pre-set amount.
Potentiometer or solid state type
thermostat readjusts set-point to
match evaporator temperature to
a varying load.
Pneumatic thermostat readjusts
set-point to match evaporator
temperature to a varying load.
Increase in temperature opens
regulator; decrease in temperature
closes regulator. Also reverse acting
with “O” variation.
Pilot position is proportional to
electronic signal.
Same as standard regulator
except controlled pressure is
sensed away from regulator.
Main regulator modulates,
closes or opens in response to
remote pilots.
Can be built into most of the
A4A variation regulators.
Has a Modudapter® and two
Moduplates® .
A4
A4S
A4B
A4D
A4K
A4O
A4OE
A4L
A4M
A4P
A43P
A4T
A4OT
A4OTE
A4J
A4E
A4OE
etc.
A4R
A4Z
1. Evaporator pressure control
2. Condenser pressure control
3. Any inlet pressure control
1. Open for temperature control
2. Closed for defrosting
1. Wide open for maximum cooling
2. Regulating for defrost
3. Regulating for temperature
control.
1. Higher pressure for defrost
2. Higher pressure for temperature
control.
3. Internal pressure relief.
1. Defrost relief
2. Non-atmospheric relief
3. High to low relief
1. Crankcase pressure regulation
2. Hot gas bypass; booster loading
3. Receiver pressure control
1. Liquid pump relief regulator
2. Reduce liquid or vapor line
pressure
1. Precise control of process
cooling
2. Liquid chillers
3. For load change compensation
1. Precise control of process
cooling
2. Liquid chillers
3. For load change compensation
1. Process cooling systems
2. Liquid chillers
3. Systems with load change
4. Heat reclaim
1. Precise control
2. Liquid chiller
3. System with load change
1. Low Pressure drop (A4AE)
2. Hot gas bypass (A4AOE)
1. Simple inventory of regulator
and pilots
2. Convenient placement of pilots
3. Unusual pilots or circuits
Versatile unit for inventory along
with Modules on pages 372-374.
Technical Information