Refrigerating Specialties Division
3
Disassembly and Assembly
(continued)
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 modulating plug
with fine crocus cloth. Inspect the seating area of the Modulating 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.
Basic Modules
(Used on A4AOS/A4AOSE)
Disassembly and Assembly
Refer to exploded views (Figs. 3 and 4), illustrating the Modular Solenoid
Pilot and Moduplate. These modules are used only with the A4AOS/ A4AOSE
Outlet Pressure Regulator with Electric Shut Off. The Modudapter, Item #28
(Fig. 2) accommodates these modules. The Pilot Solenoid is mounted on Pad
#1 of the Modudapter along with the Moduplate, item #52, mounted on Pad
#2 with the “S” showing to the outside of the regulator.
Before disassembling and assembling any modules, refer to page 2 of this
bulletin and to Bulletin RSB, Safety Procedure for Refrigerating Specialties
Division Refrigeration Control Valves.
