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INSTALLATION OF UNIT
32
Evaporator Fan Adjustment
Use the following procedure to determine the proper adjustment of the evaporator fan for a spe-
cific application.
1
Determine total system external static pressure (In mm water column) with accessories
installed. to accomplish this:
1) Obtain the design airflow rate and the design external static pressure drop through the dis-
tribution system. Your sales representative or the design engineer can provide you with
these values.
2) Using the table from unit Service Manual, add static pressure drop of the accessories
installed on the unit.
3) Add the total accessory static pressure drop to the design external static pressure. The
sum of these two values is the total system external static pressure.
2
Use the table(s) in the Service Manual to find the external static pressure (In mm water col-
umn) that most closely approximates total system external static pressure. Then locate the
appropriate airflow rate (on CMM) for your unit. The value obtained represents the break
horsepower for the evaporator fan motor and the fan RPM.
NOTE
!
• Fan Break Horsepower (BkW) listed in the Table is the percentage range of nameplate
amperage the motors will safely work within, before an oversized motor is required.
The indoor fan speed is changed by opening or closing the adjustable motor sheave. See Figure 8.
To Increase CMM
Loosen the pulley adjustment set screw and turn sheave clockwise.
To Decrease CMM
Loosen the pulley adjustment set screw and turn sheave counterclockwise.
NOTE
!
•The actual external static pressure may varies from design ESP due to actual duct work in-
stallation. The required air flow should be respected to provide the design cooling capacity.
To Decrease CFM
To Decrease CMM
To Decrease CFM
Adjustment set screw
To Increase CFM
To Increase CMM
To Increase CFM
Figure 8
To Decrease CMM
To Increase CMM
Adjustment set screw
Adjustment nut
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