Carrier 48GC04 Service And Maintenance Instructions page 7

Low Speed Fan Adjustment (Single Phase and 3-Phase units)
2-Pin DIP Switch
The 2-pin DIP switch is common to both the single and 3 phase
unit control boards (see Fig. 7 and 8). When replacing UCB,
the board will be shipped as default without a low speed select-
ed. Use the 2-pin LOW SPEED DIP switch to set the low
speed. To select correct GC low fan speed, set Dip Switch 1 to
the "ON" position (see Table 1). The dip switch positions can
also be found on the unit's control label diagram.
Table 1 — LOW SPEED 2-Pin DIP Switch Settings
LOW SPEED
DIP1
0
1
5-Pin DIP Switch (Single Phase units only)
On single phase units, the approximate static pressure of the
ductwork must be set for optimal unit efficiency. The unit is fac-
tory 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. 10. Switches 2 and 3 are used to determine the
unit tonnage. Switches 4 and 5 are used to match the motor and
drive combination. Table 2 details the various settings for the
5-pin DIP switch.
SWITCH 1
5-PIN DIP
Fig. 10 — Detail – 5-Pin DIP Switch
QUICK
ENABLE/DISABLE
DIP1
1
1
1
1
1
1
1
1
1
% OF USER SET
FAN SPEED
DIP2
0 100%
0 75%
Table 2 — LOW SPEED 5-Pin DIP Switch Reference
UNIT TON REFERENCE
DIP2 DIP3
0 1
0 1
0 1
1 0
1 0
1 0
1 1
1 1
1 1
Units with SystemVu™ controls
On units equipped with the factory-installed SystemVu con-
troller the Fan Speed settings are accessed through the
SystemVu interface.
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. 11), calculate the RPM from the CFM and ESP for the
base unit.
3. If installing any accessories listed at the bottom of the Set
Up Label, add accessory RPM to base unit RPM in upper
portion of label.
NOTE: The Fan Speed Set Up labels are located on the High Volt-
age cover in the Control Box.
4. Press any key on the SystemVu interface to activate the
display backlight and then press the MENU key.
5. Using the UP and DOWN arrow keys highlight SET-
TINGS and then press ENTER.
6. Use the DOWN arrow key highlight the UNIT CONFIG-
URATIONS menu then press ENTER.
7. Highlight UNIT CONFIGURATIONS then press ENTER.
8. Highlight INDOOR FAN and then press ENTER.
9. Refer to the job specifications to set the following, deter-
mining the values per the RPM Calculator label (see
Fig. 11). Use the UP and DOWN arrow keys and the
BACK key to set the values. Press ENTER after setting
each value to continue to the next selection.
• IDF VENT SPD
• IDF HEAT SPD
• IDF LOW COOL SPD
• IDF HIGH SPD
• IDF FREE COOL SPD
For further details see the FC/GC Series Single Package Roof-
top Units with SystemVu Controller Controls, Start-up,
Operation and Troubleshooting manual.
UNIT/MOTOR REFERENCE
DIP4 DIP5
0 1
1 0
1 1
0 1
1 0
1 1
0 1
1 0
1 1
7
UNIT APPLICATION REFERENCE
3 ton with Low static motor option
3 ton with Medium static motor option
3 ton with High static motor option
4 ton with Low static motor option
4 ton with Medium static motor option
4 ton with High static motor option
5 ton with Low static motor option
5 ton with Medium static motor option
5 ton with High static motor option