Page 94 IM-738
4. Tag the valves as a warning for the technician who will be
restarting the units
5. Note: steps I. to 4. are not necessary if the unit had not yet
been started.
Gas Furnace
If the unit is equipped with a gas furnace, close the gas shutoff
valve and open furnace control switch S3.
Control Compartment
1. McQuay International recommends that the electronic con-
trol equipment in the unit be stored in a 5% to 95% RH
(non-condensing) environment.
2. It may be necessary to put a heat source (light bulb) in the
main control panel to prevent the accumulation of atmo-
spheric condensate within the panel.
3. The location and wattage of the heat source will be depen-
dent on local environmental conditions.
4. Check the control compartment every two weeks to pro-
vide that the heat source is functional and is adequate for
current conditions.
Restart
After extended storage, a very complete start up must be per-
formed. Inevitable accumulations of dirt, insect nests, etc. can
contribute to problems if not cleaned out thoroughly prior to
start up. In addition, thermal cycling will have tended to loosen
mechanical and electrical connections. Following the start up
procedure will help discover these and other issues that may
have developed during the storage interval.
Gas Furnace
For information on maintenance of the gas furnace, refer to
Bulletin No. IM 684 or 685.
Bearing Lubrication
Motor Bearings
Supply and return fans - Supply and return fan motors should
have grease added after every 2,000 hours of operation. Use
one of the greases shown in Table 22 on page 94. Using the
following procedure, relubricate the bearings while the motor
is warm, but not running.
1. Remove and clean upper and lower grease plugs.
2. Insert a grease fitting into the upper hole and add a small
amount of clean grease with a low pressure gun.
3. Run the motor for five minutes before replacing the plugs.
Note: Specific greasing instructions may be found on a tag
attached to the motor. If special lubrication instruc-
tions are on the motor, they will supersede all other
instructions.
Condenser fan - Condenser fan motors are permanently lubri-
cated and require no periodic lubrication.
Fan Shaft Bearings
Fan shaft bearings should be relubricated periodically. Re-
lubricate according to the schedule shown in Table 23. If the
bearings are exposed to wet conditions, wide temperature
variations, or other severe atmospheric conditions, relubri-
cate more frequently. Use one of the greases shown in
Table 22.
While the bearing is at normal operating temperatures, rotate
the fan by hand and add only enough grease to purge the
seals. The seals will bleed slightly when this has occurred.
Do not overlubricate.
Table 22: Recommended greases
Table 23: Recommended Fan Shaft Bearing
Lubrication Intervals
Vibration Levels
Each unit as shipped has been trim-balanced to operate
smoothly. To provide satisfactory operation after shipping
and installation, use the accepted industry guidelines for field
balancing fans. See Table 24.
Table 24: Vibration Levels
Note: Excessive vibration from any cause contributes to premature fan and
motor bearing failure. Overall vibration levels should be monitored every six
months of operation. An increase in levels is an indication of potential trouble.
Vibration Causes
1. Wheel imbalance.
a. Dirt or debris on wheel blades.
b. Loose setscrews in wheel hub or bearing-to-shaft.
c. Wheel distorted from overspeed.
2. Bent shaft.
3. Drive faulty.
a. Variable pitch sheaves - Axial and radial runout of
flanges; uneven groove spacing; out of balance. Also
similar faults in driven sheave.
CAUTION
Bearing overheating potential. Can cause damage
to the equipment.
Do not overlubricate bearings.
Use only a high grade mineral grease with a 200°F safe
operating temperature. Refer to Table 22 on page 94 for
specific recommended lubricants.
MANUFACTURER PRODUCT
NAME
TEMP.
RANGE (°F)
Texaco Lubricants Co. Premium RB -30 to 300
Keystone Ind. Lubricants 84EP-2 -40 to 200
Mobil Oil Corporation Mobilith AW2 -40 to 325
Chevron U.S.A. Inc. SRI-2 -20 to 325
Exxon Company. U.S.A. Ronex MP -40 to 300
Shell Oil Company Alvania No. 2 -20 to 240
OPERATING
DUTY
BEARING AMBIENT TEMPERATURE
TO 130°F TO 150°F OVER 150°F
Continuous 6 months 4 months 2 months
12 Hrs./Day 12 months 12 months 6 months
FAN SPEED (RPM) VIBRATION
800 or less 5 mils maximum displacement
801 or greater 0.20 in/sec. maximum velocity
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