- 15 -
Check that vibration isolator mounts are
functioning well.
Inspect for any obstructions or blockages
at air intakes and discharges.
Check fan bearings are secured and no
undue noise by observe/listen using metal
bar as a conductor.
If unit equipped with belt guard, check
that it is fitted correctly and secure.
If there is any undue noise or knocking
from bearing, replace both bearings. Fan
bearing are grease for life, but larger units
with standard bearing require semi-annual
or annual lubrication at bearing greasing
nipple. Recommended lubricants are
Standard Din 51823, K3N or ISO XM2.
7.2 Drive Belt
Belts that are split or have frayed edges or
any other sign of damage (rubber shred
on floor) must be replaced in full set.
IMPORTANT
DURING
MAINTENANCE
AND
SERVICING,
UNIT
MUST
BE
COMPLETELY
ISOLATED
AND
PRECAUTIONS
TAKEN
TO
PREVENT
ACCIDENT
FROM
HAPPENING.
Check the belt tension and alignment, re-
tension and re-align if necessary. Refer to
Section 5.7 for belt tensioning procedure.
New belt drive must be re-tensioned after
the first 48 hours of operation.
For replacement of belts, remove the belt
guard before starting work. To change the
belts, first loosen the adjusting screw and
move the motor towards the fan to enable
old belts to be taken off and put on of
new belts. (Matched belts must be used)
Tension the belts by following instruction
at Section 5.7.
7.3 Coil Section
Periodic cleaning of coils is required. Dirty
coils have tendency to increase airside
pressure drops and reduce cooling/heating
efficiency. Dry cleaning is done by using a
powerful vacuum cleaner on the dust-
accumulated side. If coil is very dirty, coils
need to be removed for wet cleaning by
trained personnel. Ensure coil fins are not
damage
when
performing
dry/wet
cleaning. In the event that fin edges have
been bent, treat with aid of a coil comb.
Check that frost protection is working
before starting of each winter season.
Ensure the frost sensor is correctly
installed and working within desired
temperature range.
For direct expansion coils, do not use hot
water or steam to clean these coils. During
normal operation, the fin block must not
be ice up. If this occurs, check the
refrigeration system.
Check that drain pan and drain trap are
free
from
blockage
and
water
accumulation at pan.
7.4 Filter Section
During system start up, filters are likely to
become rapidly blocked.
Disposable filters and bag filters must be
replaced each time when pressure drop
reaches the indicated dirty condition by
D.M. Manometer. Washable filters must be
cleaned periodically.
7.5 Dampers
Check for dirt accumulation, damage and
sign of corrosion. Clean with cloth or high
pressure air. Check damper blade turning
manually or central control for smooth
operation.
Table 4 - Recommended Maintenance intervals (based on 12 hours operating time per day)
Component
Description
Action
Maintenance interval
Weekly Monthly 3 Monthly 6 Monthly Yearly
Fan / Motor
Fan in general
Check / Clean
●
Fan bearing
Check / Replace / Greasing
●
Motor in general
Check / Clean
●
Motor bearing
Check
●
Motor temperature
Check / Repair / Replace fan
●
Belt drive tension
Check / Re-tension
●
V-Belt condition
Check / Replace
●
Corrosion
Check / Treat / Repair
●
Bolt & nut secure
Check / Tighten
●
