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Service
ASSEMBLING THE COMPRESSOR
Before considering reassembly of the compressor, you
must determine what parts are to be reused and what
parts are to be replaced. If the compressor is of an early
style, check with the nearest YORK office to see what
updates are implemented and recommended. Carefully
examine all components and try to determine the cause
of failure (if a failure prompted the disassembly).
Major cast components seldom require replacement. If
bearings have failed radically and spun in the bearing
housings, certify the bore diameters. Bearing housings
are usually replaced, oil sumps can possibly be salvaged
at the OEM's facility. Thrust failure resulting in severe
impeller contact can destroy the inlet seals and some-
times cause stress cracks in the diffusers. Standard com-
pressors handling sour hydrocarbon gas or any gas with
hydrogen sulfide component may suffer bolt failure due
to metal embrittlement. Look for encrustation or buildup
of foreign material on the wheels. Deposits of sludge
and dirt in the systems may be the root causes of fail-
ure, and if not corrected, will cause premature prob-
lems again. There should be sufficient precision tools
available including but not limited to at least three dial
indicators; one standard Starret 196, a .0005: for the oil
pump and a long travel, (at least .250"), to measure the
rotor axial during assembly, a 6" vernier caliper, direct
reading dial if possible, and several sets of feeler gauges
with extra leafs in .002" through .008". Inside and out-
side micrometer sets are also useful.
1. Carefully inspect the rotor. If no apparent damage
or excessive runout is detected, it can usually be
reused. Look for severe shaft labyrinth rubs, the
shaft may be bent or out of balance. If you have
good bearings, you can check it with a dial indica-
tor while it's in the casing. If not, you must put the
rotor between centers in a lathe. Unbalance may
not be detectable. Any rotor repairs must be done
at the YORK factory.
2. Certify all shaft journal diameters. Shaft laby-
rinth seals and balance piston seals will usually
show some light contact. If the lands show heavy
contact they should be replaced. (See Table 12
for typical clearances.)
3. Inspect all new parts. Be sure they are the correct
items. Physically try all bearings on the rotor and
in the bearing housings before starting assembly.
Check clearances. Fit labyrinth seals around the
impellers and shaft. Check clearances with a feeler
gauge.
60
4. Clean all casing parts thoroughly. Pay special at-
tention to the diffuser grooves. Minute particles can
displace the diffusers enough to upset the labyrinth
clearances. Clean all diffuser parts, using a fine
file to carefully dress all surface nicks and burrs.
Do not remove excessive amounts of metal.
5. Using the lower casing half as a template, cut and
fit the casing flange gasket. This gasket is 1/32"
thick +.003" to -.000". Material must be compat-
ible to the refrigerant and oil being used. Use the
YORK part number on the as-built print or current
production material. Cement the gasket to the lower
casing half. (Use YORK Part N o. 013-02674-000,
3MSPW77 or equal.)
Fitting the Rotor
1. Set the first stage diffuser entrance plate in posi-
tion in the casing. Using the proper thickness com-
pressor ends gasket (27). Install the PRV housing,
be sure to slack off the rigging so the PRV rests in
the bottom half. Insert at least four screws and
tighten them. Check to be sure the casing splitline
gasket is a tight fit to the PRV housing gasket. Place
the first stage labyrinth seal ring (156) in the dif-
fuser and secure it with the spring retaining washer
(155). Install the suction end oil seal and bearing
housing. (See Removing Suction End Oil Seal.)
If proximity probes are used, a special
sleeve and mandrel must be used to
set the probes and install the bearing
housing. See the as-built print for in-
structions. Do not use the sleeves as a
buildup bearing. If you have a used
bearing in good condition, use it. If
you must use the new bearing, be very
careful of the ID surface. Use plenty
of Molycote and oil.
2. Screw guide pins into the casing and fit the correct
number of gaskets, (27, 105, 106), over the sump.
Install the discharge end oil seal in the sump. (See
Replacing Discharge End Oil Seal.) Do not fit the
oil reservoir piston ring or discharge end bearing
at this time. If proximity probes are used, fit the
special sleeve in the sump.
3. Inspect and condition the rotor journals. Using a
nylon or equal rope sling, lift the rotor and ease it
into the casing. Coat the rotor journals, suction end
oil seal, sleeve or bearing, as the case may be, with
FORM 220.11-NM2 (602)
YORK INTERNATIONAL
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