Carrier DC-12175, Руководство по установке, Страница: 85 / 104

6--4 T--311
considered when making the aforementioned
measurements.
The next step is to lay the straight edge flush across the
face of the driven pulley. This is the best way to
determine angular misalignment. Again, adjust as
required. You should repeat this step for all pulleys until
acceptable alignment is achieved. Note the drive pulley
is the primary guide for alignment. Do not use idlers as a
guide for proper component belt alignment as bearing
play could give you false readings.
6.3.4 Drive Belt Tension-Guidelines
Proper belt tension is essential for not only belt life, but
also the alternator and compressor life as well. Heat is a
major enemy of compressors and alternators that can
cause unnecessary stress and greatly reduce
component life.
Listed in Figure 6-8 are the examples specific to belt
tension concerns:
A. Under tension would promote belt slippage causing
excessive heat. Heat equals premature alternator
and/or compressor failure.
B. Over tension could cause premature bearing failure
and excessive wear on drive and driven components.
Proper belt tension is obtained by referring to Figure 6-8
. Find the belt used and where applied (compressor or
alternator drive, Single ”V” or Poly ”V” 4-8 ribs).
Notice that new belt tension is higher than in-service or
re-tension amount. All new belts require a run-in period.
During this period, a new belt will stretch more in a 10
hour run time than the entire life of the belt. So it is
important to recheck belt tension after run-in or
re-tension new belts if less than re-tension amount
prescribed above. You should check belt tension with
the belt ”hot.” However, the belt must be allowed to cool
before re-tensioning. Drives which incorporate
automatic tensioners do not require a run-in period or
re-tensioning.
6.3.5 Measuring Methods for Belt Tension
There are several methods and tools available for
determining belt tension. The industry’s acceptable
method would be to use a belt tension gauge as
manufactured by Kent-Moore or approved equal (CTD
Part Numbers 07-00203-00 for non-cogged V-belts &
07-00253-00 for Poly-V’s). There are also several other
models available than can be used. Please follow
manufacturer guidelines regarding gauge selection
operation and calibration requirements. You must get
the correct tension gauge for your specific belt type(s).
Drive Belt Top Width
New Belt
Lbs. Tension
Re-Tension
Lbs. Tension
Re-Tension
Threshold
Alternator All 110 90 70
Compressor All 130 105 80
Poly-Rib Belt
& Serpentine Drive
6 or More Ribs 145 105 90
Figure 6-8 Belt Tension Guide
6.4 COMPRESSOR INSTALLATION
6.4.1 Installation Position
The compressor should be installed on the vehicle
within the range shown in Figure 6-9. If installed outside
the range shown in Figure 6-9 the compressor will be
adversely affected. Most split system compressors are
equipped with a pressure feed lubrication system which
cannot function properly if the compressor is installed
outside this range. As a precaution, it is recommended
that once the compressor is mounted in its proper and
final position, the compressor clutch is turned over by
hand at least 10 revolutions before installation of the
drive belt up to the pulley. If this is not done before the
compressor is put into service, damage to the compres-
sor valves can result from oil slugging. This is not cov-
ered under warranty.
6.4.2 Installation Precautions
The new compressor is (should be) filled with the specif-
ic quantity of compressor oil and nitrogen gas. When
mounting the compressor on the vehicle, take the fol-
lowing steps:
a. Loosen the discharge side connector’s cap and gent-
ly release the nitrogen from compressor. Take care
not to let oil escape.
b. Slowly rotate the compressor’s magnetic clutch sev-
eral times by hand to distribute the oil which has
settled in the cylinders.
c. When replacing the compressor on a system, the
compressor should be installed after adjusting the
amount of oil. (Refer to T-299 Operation and service -
Split Systems) When installing the compressor on a
new system, be sure to follow factory guidelines.
6.4.3 Mounting Compressors
Clearance between the compressor mounting supports
(ears) and its bracket must be less than 0.004 inches
(0.10mm). Use shims as necessary to adjust this clear-
ance. This will reduce the stress on the compressor
which can cause components to fail. Be sure to maintain
proper pulley alignment for the drive belt.
It is important that the compressor be mounted properly
when installed (See Figure 6-9). The side to side mount-
ing angle of the compressor must remain
±
45
°
from the
horizontal. The forward to backward angle must be with-
in
±
10
°
of horizontal.