Emerson 3000/ITR manual 7.2Filters, 7.3Blower Package, 7.3.1Fan Impellers and Bearings, 7.3.2Belt

Component Operation and Maintenance

7.2Filters

Filters are usually the most neglected item in an environmental control system. To maintain efficient operation, they should be checked monthly and changed as required. Because replacement intervals vary with environmental condition and filter type, each unit is equipped with a filter clog switch. This warns of restricted airflow through the filter compartment by activating the Change Filter alarm.

Turn power Off before replacing filters.

Liebert Challenger 3000 Liebert and Challenger ITR filters are 28-1/2" by 29-1/2", either 2" or 4" thick, plus an optional 2" thick pre-filter. The filter is replaced from the front of the unit. On upflow units, the filter is vertical, in front of the lower compartment. Pull the filter out toward you to remove it. On downflow units, the filter is horizontal, above the electrical panel. Slide the filter out toward you to remove it.

After replacing the filter(s), test the operation of the filter clog switch. Turn the adjusting screw coun- ter clockwise to trip the switch — this will energize the Change Filter alarm. To adjust the switch pro- ceed as follows: With the fan running, set the switch to energize the light with clean filters. The unit panels must all be in place and closed to accurately find this point. Then turn the adjusting knob one turn clockwise, or to the desired filter change point.

7.3Blower Package

Periodic checks of the blower package include: belt, motor mounts, fan bearings, and impellers.

7.3.1Fan Impellers and Bearings

Fan impellers should be periodically inspected and any debris removed. Check to see if they are tightly mounted on the fan shaft. Rotate the impellers and make sure they do not rub against the fan housing.

Bearings used on the units are permanently sealed and self-lubricating. They should be inspected for signs of wear when the belt is adjusted. Shake the pulley and look for movement in the fan shaft. If any excessive movement is noticed, bearings should be replaced. However, the cause of the wear must be determined and corrected before returning the unit to operation.

7.3.2Belt

The drive belt should be checked monthly for signs of wear and proper tension. Pressing in on belts midway between the sheave and pulley should produce from 1/2" to 1" (12 to 25 mm) of movement. 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.

NOTICE

Risk of improper adjustment. Can cause equipment damage.

After adjusting or changing the belt, check to ensure that the motor base nuts are tightened. The bottom adjustment nut should be finger tight. The top locking nut should be tightened with a wrench.

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