Refrigerating Specialties Division
4
Installation
All regulators are packed for maximum protection. Unpack carefully.
Check the carton to make sure all flanges and other items are
unpacked. Save the enclosed instructions for the installer and eventual
user.
Do not remove the protective coverings from the inlet and outlet of the
regulator until the regulator is ready to be installed. Protect the inside
of the regulator from moisture, dirt and chips before and during
installation. When welded or brazed flange connections are used, all
slag, scale and loose particles should be removed from the flange
interior before the regulator is installed between the flanges. It is
advisable to install a close-coupled companion strainer (RSF) at the
inlet of the regulator to help protect it from any foreign material in the
system.
The A4A series of regulators will give optimum performance if mounted
in a horizontal line in a vertical position with the manual opening stem
on bottom. Where other positions are desired, the factory should be
consulted; please give application and piping details. The regulator
must be installed with the arrow on the valve body pointing in the
direction of the fluid flow for the regulator to function properly. Backward
flow through the regulator is uncontrolled and will vary with the valve
model and the reverse pressure drop encountered. The regulator is
not a check valve.
Tighten the flange bolts and nuts evenly to provide proper seating of
the flange gasket and to avoid damage to gaskets or flanges. (See
Flange Bolt Torque Table, page 16) Avoid using the regulator flange
bolts to stretch or align pipe. Even the heavy duty semisteel body of
an A4A can be distorted, causing the precision parts to bind.
The regulator should be installed in a location where it is easily
accessible for adjustment and maintenance. The location should be
such that the regulator can not be easily damaged by material handling
equipment. When it is necessary to insulate the regulator (and
companion strainer), the insulation should be installed to provide
access to the regulator (and companion strainer) for adjustment and
maintenance. Do not insulate the solenoid coil and coil housing. Proper
indicating gauges should be installed to be easily visible to the
operating engineer for system checking and adjusting purposes.
Disassembly and Assembly
Refer to the exploded views, Figs. 6 and 7, in this section.
Before disassembling any A4A type regulator, read the information in
this bulletin and Bulletin RSBCV, Safety Procedures for Refrigerating
Specialties Division Refrigeration Control Valves.
Before a regulator is removed from the line or disassembled in the
line, make sure that all refrigerant has been removed from the regulator,
including the bonnet where applicable, and the close coupled strainer.
The regulator must be isolated from the rest of the system in a safe
manner. When pumping down to remove the refrigerant, the manual
opening stem 33A must be turned out (counter clockwise) to make
sure the valve is open.
Disassembly and Assembly (continued)
All A4A Regulators General Procedure
The construction of the regulator and the method of disassembly are
relatively simple, but some procedures must be followed to avoid
damage. The following describes the procedure for the basic A4A;
special instructions for other types are included in other appropriate
sections.
Disassembly - Take care when removing Seal Caps 1 and 44 in case
some refrigerant may be trapped inside. Back the Adjusting Stem 6
all the way out to remove any pressure from Range Spring 13 otherwise
damage to Diaphragm 17 or Pilot Seat 18 may occur. Remove Bonnet
8 by carefully removing Cap Screws 11. Take care not to damage
Diaphragm Follower 15. Remove Adapter 28 by removing Cap Screws
31. Turn the Manual Opening Stem 33A all the way in until the flats on
the stem barely protrude from the stuffing box nut. Push Piston 30
down against the spring force. The piston should move freely down
and be returned by the spring force. If the piston is jammed or sticky,
remove Bottom Cap Assembly which includes Items 33 through 42
by removing Cap Screws 39 or unscrewing Bottom Cap, 20mm
through 32mm (3/4” through 1-1/4"). Using a hard wood dowel rod
inserted through the bottom of the valve, tap the piston upward and
out. Thoroughly clean all parts. If jamming has taken place and the
piston and bore are scored, remove all burrs by polishing the piston,
bore and throttling plug with fine crocus cloth. Inspect the seating
area of the Throttling Plug 33 for damage or erosion. If damaged it
should be replaced. It would be advisable to replace the entire bottom
cap assembly. Inspect all gaskets and “O” rings for damage and
replace where necessary.
Assembly - When reassembling the valve, all internal parts should
be clean, dry and lightly oiled with refrigerant oil, except “O” rings.
Apply silicone grease to the “O” rings. Care must be taken especially
when the parts are cold since moisture can condense on parts and
cause rapid rusting. When replacing gaskets, they should be oiled
very lightly with refrigerant oil before assembly. Install bottom cap
assembly first and tighten in place. Carefully replace the piston; never
try to force it in place. Align the Adapter Gasket 29 carefully with the
proper holes in the adapter and valve body and fasten adapter in
place. Before assembling the bonnet be sure the Adjusting Stem 6 is
turned all the way out and that the Bonnet 8 and Diaphragm Follower
15 are properly aligned, otherwise damage to the diaphragm and pilot
seat may occur. Place Gasket 19 in the adapter and align Gasket 16
and Diaphragm 17 to the center of the bonnet. The raised center of
the diaphragm must be towards the bonnet. For range “D” use two
diaphragms. Tighten Cap Screws 11 evenly. The ideal tightening torque
is 1.5 Kg-m (11 ft. lbs.). Valve is now ready to be adjusted for normal
operation.
If close coupled strainer is used, it may be cleaned before putting the
valve back in operation. The regulator must be tested for leaks with
refrigerant gas or other appropriate gas before the system is put into
operation.
18
1
2
3
4
5
6
8
11
9
10
12
13
14
15
16
61
17
19
48
49
62
63
64
65
50
66
50
S6A MODULAR SOLENOID PILOT
(For A4 - Port Sizes 20-100mm
3/4" - 4")
A2D2, A2D MODULAR
PRESSURE PILOT
A2D2 Port Sizes 20-50mm
(3/4" - 2")
A2D Port Sizes 65-100mm
(2½" - 4")
Fig. 7
69
68
67
70
71
58