Refrigerating Specialties Division
5
Disassembly
Back out the adjusting stem 6 to remove all tension
from the Range Spring 13. This is necessary to
avoid possible damage to internal parts of the
regulator. Remove Bonnet Screws and disas-
semble parts. Normally parts 8 through 15 do not
require disassembly. Inspect parts for dirt, corro-
sion and wear and clean and replace as needed.
Inspect Pilot Seat 96 (A4AT) top seating surface for
dirt, wear or damage. Remove from valve body and
clean, lap on a flat plate or replace as necessary.
Examine the diaphragm region which contacts the
seat surface; look for dirt heavy scratches or corro-
sion. If the diaphragm cannot be easily wiped clean,
it should be replaced. Check the movement of the
push pin 101. If it does not move smoothly, the
thermal element should be removed and the push
pin, adapter, o-ring, and pilot body cleaned thor-
oughly. 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, 3/4" through 1-1/4" (20mm through 32mm).
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 advis-
able 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. Items which require
several bolts to fasten must be tightened uniformly
to provide proper alignment and seating. (See Bolt
Torque Table). 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 the
valve body and fasten adapter in place. Before
assembling the bonnet be sure the adjusting Stem 6
is turned all the way out. Place Gasket 97, Dia-
phragm 17 and Gasket 16 in Pilot Body 98. The
raised center of the diaphragm must be towards the
bonnet. Stack Diaphragm Follower 15, Lower
Spring Rest 14, Spring 13 and Upper Spring Rest 12
on top of diaphragm and carefully lower bonnet in
place and tighten Screws 11 in place. Make sure
two diaphragms are used for Range +60
o
F to 140
o
F
(20
o
C to 60
o
C). Tighten Cap Screws 11 evenly.
The ideal tightening torque is 11 ft. lbs. (1.5 kg-m).
Valve is now ready to be adjusted for normal opera-
tion.
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.
Maintenance and Service
General Procedure
Dirt in the system is the greatest single cause of
regulator malfunction. All screens or filters must be
cleaned or replaced when they become dirty. At
start up it is especially important that these items are
cleaned or changed frequently. When the RSF
close-coupled companion strainers are used,
maintain according to instruction in Bulletin 00-10.
Moisture in halocarbon systems in particular can
cause corrosion or form ice, causing the piston to
freeze in position. Filter-driers should be used and
maintained for halocarbon systems.
Before deciding to disassemble a regulator for
servicing, the following investigations should be
made:
Check the manual opening stem; it should be turned
in for automatic operation.
Check the regulator setting to make sure it is prop-
erly adjusted. Turn adjusting screw slowly to see if
regulator responds. Check regulator pressure
range; if wrong, range spring must be replaced.
