Parker A4AL-DN Manual

DIFFERENTIAL PRESSURE
RELIEF REGULATOR
TYPE A4AL-DN
Port Size 3/4"- 4" (20-100mm)
For Ammonia, R-22, R134a, R404a, R507
and other common refrigerants.
FEATURES
• Pilot operated characterized Modulating
Plug for precise control
• Suitable for all common refrigerants and oil
• 406 psig (28 bar) design pressure (PS)
• Flanges for threaded or welded steel pipe
and copper tube (copper not for ammonia)
• Unique Modular construction
• Interchangeable parts
• Easy to Service
• Close coupled strainers, optional
• Stainless Steel Diaphragm
• Manual Opening Stem
• Complies with Pressure Equipment Direc-
tive 97/23/EC
A4AL-DN
Fig 1
Refrigerating Specialties Division
310218
BULLETIN DN23-10B
Type A4AL-DN
January 2007
Installation and Service Information
Description:
These compact, heavy duty, pilot operated, Differential
Pressure Regulators are suitable for Ammonia, R22,
R134a, R404a, R507 and other common refrigerants and
fluids approved for use in refrigeration systems.
All A4AL Regulators are pilot operated using upstream
pressure for the opening force and require a minimum 2
psi (0.14 bar) pressure drop to fully open.
These valves are generally ordered with close coupled
upstream strainer to prevent entrance of foreign material
into the valve and the rest of the system.
Purpose:
Modulates flow of refrigerant liquid or gas to maintain a
constant set-for pressure differential between regulator
inlet and regulator outlet.
Regulator applications are as follows: As a relief valve
from pump outlet to accumulator of a liquid recirculating
pump system to prevent pump overload or dry pumping
when evaporator liquid solenoid valves are closed.
Differential pressure will not vary despite fluctuating
accumulator pressures. As a gas or liquid pressure
regulator whenever it is desired to maintain a set-for
pressure difference between regulator inlet and outlet.
The fluid temperature range for the A4AL Series of
Regulators is -50°F to 220°F (-45°C to 105°C).
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