Parker A4W Series Installation And Service Information
Adaptomode weld-end pressure regulators
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ADAPTOMODE WELD-END
PRESSURE REGULATORS
Types: A4W-DN, A4WE-DN,
A4WS-DN, A4WB-DN, A4WD-DN,
A4WP-DN, A4WOE-DN, A4WR-DN
Port Size 125-200mm (5"-8")
FOR AMMONIA, R12, R22, R502
AND OTHER COMMON REFRIGERANTS
FEATURES
• Cast Steel Body – Strong, Lightweight.
• Welds Directly in the Line – No Flanges.
• Removable Seat – Serviceable from Top Side.
• Streamlined Fluid Flow Pattern.
• Unique Modular Construction – Same Modules
as A4A-DN Series.
• Interchangeable Parts.
• Pilot Operated Characterized Modulating Plug for
Precise Control.
• Suitable for All Common Refrigerants and Oil
• 25 bar (362 psig) Design Pressure (PS).
• Many Control Variations are Possible with the Use
of a Few Modules and Kits.
• Stainless Steel Diaphragm.
• Stainless Steel Pilot Seat.
• Manual Opening Stem.
• Complies with Pressure Equipment Directive 97/23/EC
SEAL CAP
MANUAL
OPENING
STEM
POWER PISTON
REMOVABLE
SEAT
Fig. 1 – A4W, A4WE
Refrigerating Specialties Division
310221
SEAL CAP
ADJUSTING STEM
RANGE SPRING
DIAPHRAGM
GAUGE CONNECTION
PILOT SEAT
MODULATING PLUG
CLOSING
SPRING
BULLETIN DN23-20
A4W Series
February 2002
Installation and Service Information
Description
These heavy duty, cast steel bodied (ASTIM No. A352 Grade LCB),
pressure regulators weld directly in the line and do not require flanges.
They are used for control of Ammonia, R-12, R-22 and R-502, and other
common refrigerants, certain oils and other fluids approved for use in
refrigeration systems.
The A4W Series Regulators are pilot operated, using upstream pressure
for the moving force, and require a minimum 0.14 bar (2 psi) pressure
drop to fully open. The basic Type A4W is an Inlet Pressure Regulator
which tends to open on a rise in upstream pressure above set-point and
to close on a drop in pressure below set-point.
These valves can be ordered with the Type RSW Strainer to be welded
directly to the inlet of any of the Type A4W Regulators or use a 13mm (1/
2") Type RSF Strainer in only the pilot circuit of a Type A4WE or A4WR
version of the regulator.
The A4W Series of regulators uses the same Modules as does the A4A
Series to configure many possible variations.
Purpose
The purpose of the Type A4W Series of Pressure Regulators is to modulate
the flow of refrigerant gas and/or liquid so as to maintain a constant set
for pressure, regardless of load fluctuations. The regulators described in
this bulletin control upstream (inlet) pressure except for the Type A4WOE,
which controls downstream (outlet) pressure.
The fluid temperature range for the A4W Family of Regulators is -45° to
105°C (-50° to 220°F).
Principles of Operation (See Fig. 1)
The inlet pressure enters the space under the Diaphragm through passage
N. When the force created by the pressure exceeds the force of the Range
Spring, the Diaphragm is lifted off of the Pilot Seat, allowing pressure to
enter on top of the Power Piston. This causes the Power Piston to move
downward, forcing the Modulating Plug to open and modulate to maintain
constant inlet pressure. (See pages 3 - 5 for principles of operation of
other A4W Variations.) An increase in inlet pressure lifts the Diaphragm
further, allowing more pressure on top of the Power Piston and opening
the valve wider. A decrease in inlet pressure causes the Diaphragm to
move closer to the Pilot Seat reducing the pressure on the top of the
Power Piston and allowing the Closing Spring to reduce the valve
opening.
The degree of valve opening is controlled by the amount of pressure on
top of the Power Piston, which in turn is controlled by the flow through the
Pilot Seat and the bleed off through the bleed hole in the Power Piston to
the outlet of the valve. The volume of bleed flow from the top of the Piston
to the valve outlet through the clearance between the Power Piston and
the piston bore is very small because the Power Piston is fitted with a
Seal Ring.
1
I S O
9 0 0 1
C E R T I F I E D
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Table of Contents
Related Manuals for Parker A4W Series
Summary of Contents for Parker A4W Series
- Page 1 2") Type RSF Strainer in only the pilot circuit of a Type A4WE or A4WR • Complies with Pressure Equipment Directive 97/23/EC version of the regulator. The A4W Series of regulators uses the same Modules as does the A4A Series to configure many possible variations. Purpose...
- Page 2 Manual Opening Stem All Type A4W Regulators are provided with a Manual Opening Stem located at the top of the valve (refer to Fig. 1 for the location of the stem and other related parts). For access to the stem the Seal Cap on top of the regulator must be removed.
- Page 3 Type A4WD (See Fig. 5) Description The Type A4WD is a Dual Inlet Pressure Regulator capable of regulating two different pressure set-points. When the integrally mounted S6A Pilot Solenoid is energized, the regulator is controlling the lower of the two set-points, which must be adjusted on the pressure pilot over the center of the main valve.
- Page 4 pressure. (Normally this is known as a “Reverse Acting” thermostat-controller.) The decrease in air pressure will lower the regulator set-point and produce a lower inlet pressure and lower evaporator or condenser temperature. Conversely, a drop in temperature at the thermostat must cause an increase in air pressure, with a resultant increase in evaporator or condenser temperature.
-
Page 5: Installation
Electrical (For A4WS, A4WB and A4WD) The Refrigerating Specialties Division molded, water resistant Class “B” solenoid coil is designed for long life and powerful opening force. The standard coil housing meets NEMA 3R and 4 requirements. This sealed construction can withstand direct contact with moisture and ice. The coil housing far exceeds the requirements of NEMA Standard ICS, 1-110.57 salt spray test for rust resistance. - Page 6 For replacement parts and prices, consult PARTS KITS LIST PRICE SCHEDULE INDUSTRIAL AND FLO-CON (PK) Fig 9 - S6A Pilot Fig. 8 Refrigerating Specialties Division...
- Page 7 Item Description otherwise damage to diaphragm 45 or Pilot Seat 44 may occur. Remove Body Bonnet 51 by carefully removing Cap Screws 58. Take care not to damage Diaphragm Follower 47. Seat Valve O-Ring Turn the Manual Opening Stem 11 all the way out (counterclockwise) to Screw, Hex Head stop.
-
Page 8: Maintenance And Service
To replace the Seal Ring 10 on the Power Piston 9 install in place by Maintenance and Service starting the new ring over the top of the Piston. Gradually engage the ring Dirt in the system is the greatest single cause of regulator malfunction. into the slot, rotating the force on the ring as it is pushed into place. -
Page 9: Troubleshooting Suggestions
TROUBLE SHOOTING SUGGESTIONS SYMPTOM PROBABLEREASON CORRECTION Regulator does not Diaphragm or Pilot Seat dirty, damaged Clean or replace. Clean strainer. shut off flow. or frozen. Diaphragm follower stuck or damaged. Clean or replace. Install follower carefully. Piston jammed with excess dirt. Remove Piston and clean dirt from Seal Ring and groove. - Page 10 Weld End Regulators, 125-200mm (5" - 8") These heavy duty, cast steel bodied pressure regulators weld directly These valves can be ordered with the R/S strainer to be welded directly in the line and do not require flanges. As with the flanged body to the inlet of any regulator.
- Page 11 PRESSURE CONTAINING COMPONENTS A4W DN LINE: 5" TO 8" 125 MM TO200 MM) Type C O M P O N EN T D ES C R I P TI O N M A TER I A L B O D Y ,5"- 8" A 4W A S TM A 352 LC B C A S T S TE E L A D A P TE R ,5- 8"...
- Page 12 Parker Hannifin Corporation and its subsidiaries at any technical expertise. It is important that you analyze all aspects of time without notice.