27
8.0 REGULAR MAINTENANCE ITEMS
8.1 Air
Filters
Filters should be checked on a regular basis and changed when they become dirty. This will ensure
effi cient operation of the unit. Spare fi lters should be kept in stock as these tend to be a frequently
replaced maintenance item. Filters may require changing as often as monthly. Note also that
construction dust on new installations will quickly clog new fi lters.
The optional Mini DAP II or Mini DAP III control panel can monitor fi lters with an optional dirty
fi lter alarm. Although the unit may have a dirty fi lter alarm, this should not be relied on as the only
determinant for replacing fi lters. A mis-adjusted fi lter differential pressure switch may not give a
proper indication of a clogged fi lter.
To check the fi lter differential pressure switch for proper adjustment, temporarily cover about 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 prematurely or does not
energize at all, the pressure switch should be adjusted. Panels must remain closed when determining
if an adjustment is necessary.
Filters 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 regularly (monthly) to ensure proper tension. If tightening is required,
loosen the four motor mounting bolts. Turn the adjustment screw on the end of the motor mounting
channel until the proper belt tension is attained. Retighten the four mounting bolts. Damage can
occur to belts that are overtightened. The amount of play in a typical driveset 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 mis-aligned the bearing life and belt life is shortened considerably.
8.3 Bearings
Bearings used on Mini Ceiling units are permanently lubricated and do not require maintenance.
8.4 Humidifi er Canisters
The optional steam generator type humidifi er does not require maintenance other than to replace the
canister as required. This frequency will depend on usage and water type. A set of manufacturer’s
instructions for the humidifi er is sent as part of the paperwork placed inside the unit when it ships.
8.5 Fuses
Always replace fuses with those of the equivalent rating with regard to: 1) amperage, 2) voltage,
and 3) speed. For instance compressors and motors are inductive loads which require time delay
fuses. Electric reheat and humidifi ers are resistive loads requiring fast acting fuses.
8.6 Heating
Elements
Heating elements do not normally require maintenance. However sometimes they may accumulate
a fi lm of dust or dirt when unused for extended periods of time. When energized, the burning debris
can create smoke or unpleasant odor. To help avoid this, periodic cleaning is recommended.
