54
Direct-Fired Make-up Air •
MUA-SVX01A-EN
Maintenance
a higher than normal temperature and noise level. Excessive leakage of grease at
the seals, and a high operating temperature suggest too much grease.
Frequency of Lubrication
Frequency of lubrication depends upon operating conditions. The bearing
operating temperature is the best index for determining a relubrication schedule.
Table 7 gives the frequency of relubrication based upon continuous operation for
various operating temperatures and can be used as a satisfactory guide for
determining when all ball and roller bearings should be lubricated.
Dampers
Dampers should be inspected monthly (daily in icy weather) for securely
fastened linkages, and smooth operation. If dampers are binding or excessively
noisy, then lubrication may be required. Place one drop of #20 weight machine
oil on each blade bearing, and linkage ball joint. Do not over lubricate, and wipe
any excess from the area. Ensure to note that dampers over 49-inches long have
intermediate bearings which require lubrication.
Air Filters
All filter banks should be equipped with a manometer or differential pressure
switch to indicate when the filters are dirty. Filters should be replaced when the
differential pressure across them reaches the manufacturer’s recommended final
value. Dirty filter elements should be replaced with a clean element of the same
type and size. In addition, it is strongly advised that the air filters be checked
every 30-daysand replaced with new filters (throw-away type) or cleaned
(washable type) as required. Cleanable filters should be given new application of
filter coating after washing to maintain optimum performance.
Table 12. Frequency of lubrication
Speed (RPM)
Temp.
Cleanliness
Interval
100
Up to 125°F
Clean
6 Months
500
Up to 150°F
Clean
2 Months
1000
Up to 210°F
Clean
2 Weeks
1500
Over 150°F
Clean
Weekly
Any Speed
Up to 150°F
Dirty
1 Week
Any Speed
Over 150°F
Dirty
Daily to 1 Week
Any Speed
Any Temp.
Very Dirty
Daily to 1 Week
Any Speed
Any Temp.
Extreme Conditions
Daily to 1 Week
