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Step 16 — Fan Speed Set Up
UNITS WITH ELECTRO-MECHANICAL CONTROLS
The fan speed set up controls are located on the lower section
of the Unit Control Board (UCB). See Fig. 55 for the location
on 3 phase voltage units or Fig. 56 for the location on single
phase voltage units.
1. Check the job specifications for the CFM (cubic feet per
minute) and ESP (external static pressure) required.
2. Using the chart on the Fan Speed Set Up labels (see
Fig. 58), calculate the Vdc from the CFM and ESP for the
base unit. Then add Vdc for any accessories installed per
the “Field Accessories” section of the label.
NOTE: The Fan Speed Set Up labels are located on the High Volt-
age cover in the Control Box.
3. Connect a multimeter to the Vdc terminals on the UCB.
4. Set the Range Switch to either A, B, or C per the Switch
Range table.
5. Using a straight blade screwdriver, turn the Vdc control
dial to fine tune the Vdc reading.
6. Record the reading in the Field Setting field.
NOTE: Fan set-up Vdc is not affected by the operating stage of
the unit.
Fig. 55 — UCB Fan Speed Controls - 3-Phase Units
Fig. 56 — UCB Fan Speed Controls - Single Phase
Units
NOTE: On single phase units, the approximate static pressure of
the ductwork must be set for optimal unit efficiency. The unit is
factory set for greater than 1.0 in. wg. If the external static pressure
is less than 1.0 in. wg, slide switch 1 on the 5-pin DIP to the “ON”
position. See Fig. 57.
Fig. 57 — Detail – 5-Pin DIP Switch
FAN SPEED SET UP CONTROLS
FAN SPEED SET UP CONTROLS
SWITCH 1
5-PIN DIP