McQuay IM 937 45
System Maintenance
System Maintenance
Planned Maintenance
Planned maintenance is the best way to help avoid unnecessary
expense and inconvenience. At regular intervals have a
qualified service technician inspect this system. The required
frequency of inspections depends on installation and operating
duty. Routine maintenance should cover the following items:
1 Tighten all belts, setscrews, and wire connections. (See
Table 14 on page 40.)
2 Clean the evaporator or economizer coils mechanically or
with cold water, if necessary. Usually any fouling is only
matted on the entering air face of the coil and can be
removed by brushing.
3 Clean the condenser and economizer tubes periodically.
Clean condenser and economizer coils chemically or
mechanically. Keep tubing clean to maintain system
performance.
4 Lubricate motor and fan shaft bearings.
5 Align or replace belts as needed.
6 Replace filters as needed.
7 Check refrigerant sightglass. If sightglass is not solid with
steady-state full load operation of unit, check for refrigerant
leaks.
Note: A partially full sightglass is not uncommon at part
load conditions. Check for proper superheat.
8 Check for condensate drain blockage. Clean condensate
pan as needed.
9 Check power and control voltages.
10 Check running amperage.
11 Check operating temperatures and pressures.
12 Check and adjust temperature and pressure controls.
13 Check and adjust linkages.
14 Check operation of all safety controls.
Bearing Lubrication
Motor Bearings
Supply and return fans—Supply and return fan motors
should have grease added after every 2000 hours of operation.
Using the following procedure, relubricate the bearings while
the motor is warm, but not running. Use one of the greases
shown in Table 16.
1 Remove and clean upper and lower grease plugs.
2 Insert a grease fitting into the upper hole and add clean
grease (Table 16) with a low pressure gun.
3 Run the motor for five minutes before replacing the plugs.
Note: Specific greasing instructions are located on a tag
attached to the motor. If special lubrication instructions
are on the motor, they supersede all other instructions.
WARNING
Improper maintenance can cause equipment damage, severe
personal injury, or death. Installation and maintenance must
be performed only by trained, experienced personnel who are
familiar with local codes and regulations and are experienced
with this type of equipment.
WARNING
Moving machinery and electrical power hazards. Can cause
severe personal injury or death.
Disconnect and lock off power before servicing equipment.
CAUTION
Sharp edges are inherent to sheet metal parts, screws, clips
and similar items. May cause personal injury.
Exercise caution and wear protective gear when servicing
equipment.
CAUTION
Bearing overheating potential. Can damage the equipment.
Do not overlubricate bearings.
Use only a high grade mineral grease with a 200°F safe
operating temperature. See below for specific recommended
lubricants.
Table 16: Recommended Lubricants and Amounts for Fan
Motor Bearings
Mfr. Grease NEMA Size
Amount to
Add (oz.)
Texaco,
Polystar
or
Polyrex EM
(Exxon Mobile)
or
Rykon
Premium #2
or
Penzoil Pen 2
Lube
56 to 140 0.08
140 0.15
180 0.19
210 0.30
250 0.47
280 0.61
320 0.76
360 0.81
400 1.25
440 2.12
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