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8.0 REGULAR MAINTENANCE ITEMS
8.1 Air Filters
Air fi lters should be checked on a regular basis and changed when they become dirty. This will
ensure effi cient operation of the unit. Spare air fi lters should be kept in stock as these tend to be a
frequently replaced maintenance item. Air fi lters may require changing as often as monthly depen-
dent on room or space conditions. New installations with construction dust will quickly clog fi lters
requiring new fi lters.
The optional Mini DAP-II or optional Mini DAP-III control panels monitor air fi lters. A dirty fi lter alarm
will be enunciated on the controls display screen. Although the unit may display a dirty fi lter alarm,
this should not be relied on as the only determinant for replacing air fi lters. A misadjusted air fi lter
differential pressure switch may not give a proper indication of a clogged fi lter.
To check the air fi lter pressure differential pressure switch for proper adjustment, temporarily cover
approximately 75% of the return air opening using heavy cardboard or similar material. The alarm
should energize when 75% of the air is blocked, simulating dirty fi lters. If the alarm energizes pre-
maturely or does not energize at all, the pressure switch should be adjusted. Panels must remain
closed when determining if an adjustment is necessary.
WARNING: Air fi lters that require changing can restrict airfl ow and create problems such
as coil icing or poor air distribution.
8.2 Belts
Belt tension should be checked on a regular basis (monthly) to ensure proper tension. If tighten-
ing is required, loosen the four mounting bolts. Turn the adjustment screw on the end of the mo-
tor mounting channel until the proper belt tension is attained. Retighten the four mounting bolts.
Damage can occur from belts that over tightened. The amount of play in a typical drive set should
be 1/2 inch. When tightening the belts make sure the pulley alignment is true. If the belts are over
tightened or if the pulleys are misaligned, the bearing life and belt life are shortened considerably.
8.3 Bearings
Blower bearings used with Mini ceiling units are permanently lubricated and do not require mainte-
nance.
Some motors have Zirk type grease fi ttings on the bearings. If so, the motor should be greased at
least annually. Use NLG1 grade 2 lithium or lithium complex grease. Care should be taken to avoid
over-greasing the bearings. Only one or two pumps from a manual gun are required.
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