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System Operation, Testing and Maintenance
Liebert
®
Mini-Mate2
™
56
9.2.3 Blower System
Monthly inspection of the blower package include: 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 bearings 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
midway 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.
9.2.4 Blower Removal
If the blower or bearings must be removed or serviced, use the following procedure.
NOTICE
Risk of refrigerant and water/glycol piping damage. Can cause leaks that result in equipment
and building damage and loss of cooling.
Use caution and do not contact piping when removing the blower motor and blower sled.
1. Remove the main center section of the three-piece electric panel by first marking and
disconnecting all power and control wiring entering the panel.
2. Remove the panel by removing screws from top and bottom sections
3. Remove the blower motor from the blower sled.
4. Remove the four bolts holding the blower sled to the base isolators.
5. Slide the blower/sled assembly forward and rotate 90°.
6. Slide the blower/sled assembly from unit after ensuring that the refrigerant and water piping are
protected from damage.
7. Reinstall by reversing this procedure.
9.2.5 Refrigeration System
Each month the components of the refrigeration system should be inspected for proper function and
signs of wear. Since in most cases evidence of malfunction is present prior to component failure,
periodic inspections can be a major factor in the prevention of most system failures. Refrigerant lines
must be properly supported and not allowed to vibrate against ceilings, floors or the unit frame.
Inspect all refrigerant lines every six months for signs of wear and proper support. Inspect the
capillary and equalizer lines from the expansion valve.
Suction Pressure
Suction pressure will vary with load conditions. Suction pressure normally ranges from 58 psi to 75
psi (405 kPa to 517 kPa).
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.