Supply Fan (Blower) Section; Supply Fan (Direct-Drive) - Carrier 48GC 04-06 Series Service And Maintenance Instructions

17 1/4"
Divider
Cleanable
Aluminum
Filter
Barometric
Relief
Fig. 3 — Filter Installation
To remove the filter, open the filter clips. Re-install the filter by
placing the frame in its track, then closing the filter clips.
MANUAL OUTSIDE AIR HOOD SCREEN
This inlet screen is secured by a retainer angle across the top edge
of the hood. (See Fig. 4.)
Screws
Fig. 4 — Screens Installed on Outdoor-Air Hood
To remove the screen, loosen the screws in the top retainer and slip
the retainer up until the filter can be removed. Re-install by plac-
ing the frame in its track, rotating the retainer back down, and
tightening all screws.

SUPPLY FAN (BLOWER) SECTION

WARNING
ELECTRICAL OPERATION HAZARD
Failure to follow this warning could result in personal injury or
death.
Before performing service or maintenance operations on unit,
LOCKOUT/TAGOUT the main power switch to unit.
Electrical shock and rotating equipment could cause severe
injury.
Outside
Air
Hood
Filter
Filter
Clip
All low-voltage wiring should be routed through the provided
raceway built into the corner post of the unit or secured to the unit
control box with the electrical conduit in order to provide UL-
required clearance between high and low-voltage wiring.

Supply Fan (Direct-Drive)

All GC units have the EcoBlue™ direct drive vane axial fan sys-
tem. The fan is driven by an ECM motor with speed that is user set
through the Unit Control Board (UCB). Speeds are fully configu-
rable from 40% to 100% of motor's maximum speed. See Fig. 5
and 6.
Motor
Plug
Fan
Rotor
ECM
Motor
Fig. 5 — Direct-Drive Supply Fan Assembly
BLUE
YELLOW
3 2 1
BLACK
6 5 4
GRN/YEL
9 8 7
WHITE
ORANGE
GRAY
Fig. 6 — ECM Motor Plug Connectors
EVALUATING MOTOR SPEED
The direct drive ECM blower motor uses a constant speed design.
Motor speed is controlled by a 0-10 vdc signal, where 10 vdc is
equal to motor's maximum rpm.
SELECTING FAN SPEED
All units come factory set for 7.8 vdc or approximately 78% of the
motor's maximum speed. Fan speed should be set per job specifi-
cation cfm (cubic feet per minute) and ESP (external static pres-
sure) required and per Fan speed set up label included on the unit's
high voltage cover. In some cases, the Fan Speed Set Up label may
already include the field setting if unit was previously installed.
Check the box on the lower half of the label to see if the field volt-
age setting was filled in and if so, set fan speed to that voltage.
Otherwise see detailed instructions below.
NOTE: Fan Speed Set-Up is for full load airflow. If the unit has
multiple stages of cooling, low cool and ventilation may operate at
4
Power L3 (3 phase only)
Power L2
Power L1
Earth Ground
CTL Signal Common
10vdc Source
0–10vdc Signal