Liebert 50 & 60Hz - Manual (Page 59)

System Operation, Testing, and Maintenance
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6.2 Maintenance and Component Operation
6.2.1 Electric Panel
The electric panel should be inspected on a semi-annual basis for any loose electrical connections.
6.2.2 Filters
Filters are usually the most neglected item in an environmental control system. In order to maintain
efficient operation, they should be checked monthly and changed as required. ALWAYS TURN
POWER OFF BEFORE REPLACING FILTERS.
Filters are replaced by opening the hinged door on the return air filter box.
6.2.3 Blower System
Monthly inspection of the blower package includes: motor mounts, belts, fan bearings, and impellers.
Fan impellers should be thoroughly inspected and any debris removed. Check to see if they are tightly
mounted on the fan shaft and do not rub against the fan housing during rotation. Motor and fan bear-
ings are permanently sealed and self-lubricating and do NOT need lubricated.
The drive belt should be checked monthly for signs of wear and proper tension. Pressing on belts mid-
way between the sheave and pulley should produce from 1/2" to 1" (12 to 25 mm) of deflection. Belts
that are too tight can cause excessive bearing wear.
Belt tension can be adjusted by raising or lowering the fan motor base. Loosen nut above motor
mounting plate to remove belt. Turn nut below motor mounting plate to adjust belt tension. If belt
appears cracked or worn, it should be replaced with a matched belt (identically sized). With proper
care, a belt should last several years.
Air Distribution
Since all unit models are designed for constant volume air delivery, any unusual restrictions within
the air circuit must be avoided. High efficiency filters can reduce air performance and evaporator
capacity.
Blower Removal (Evaporator)
If the blower or bearings must be removed or serviced, use the following procedure.
1. Prepare the main center section of the three (3) piece electric panel by first marking and
disconnecting all power and control wiring entering the panel.
2. Remove the electric panel by removing screws from top and bottom sections
3. Remove the bottom electric panel mounting flange from unit base.
4. Remove the belt, motor, motor mounting plate, and tensioning bolt.
5. Remove the four (4) screws holding the blower mounting rails to the sled.
6. Remove the (4) screws holding the blower mounting rails to the sled.
7. Slide the blower/rail assembly forward and rotate approximately 45 degrees and remove from
unit.
8. Replace failed parts.
NOTE
After adjusting or changing the belt, always be certain that motor base nuts are tightened. The
bottom adjustment nut should be finger tight. The top locking nut should be tightened with a
wrench.
!
CAUTION
Protect refrigerant and water piping from damage.