85
Table 64 — Duct Pressure Transducer
Output Characteristics.
VFD OPERATION TROUBLESHOOTING — When trou-
bleshooting the VFD drives in these units, check first that all
required conditions for VFD operation are satisfied.
The VFDs are set up to start when the base unit controls
command the supply fan to start. To start the supply fan, the
following conditions are required at the base unit controls:
1. Main power on
2. Supply Fan circuit breaker (IFCB) closed
3. Occupied status, or Unoccupied status with Heating or
Cooling demand
4. Indoor fan contactor closed on command from base
unit control
For the VFD to run, the following conditions must be met at
the VFD:
1. Drive enable jumper is installed from terminals CC-ST
(factory supplied) (see Fig. 49).
2. Proper rotation jumper is installed at terminals R-CC
(reverse rotation, factory supplied) or terminals F-CC
(forward rotation, factory supplied).
3. Emergency stop jumper is installed from terminals
S4-CC (factory supplied).
4. A 4 to 20 mA signal is applied across terminals IV-CC
(from PSIO1, Channel 16).
5. DIP Switch SW1 (located on the VFD’s printed circuit
control panel) must be set to “I” (indicating usage of a
4 to 20 mA input signal at terminal “IV”).
6. Speed Control (located on the VFD’s keypad/display)
set for “Remote” (press the “SPEED CTRL” button
until LED “REMOTE” is illuminated).
7. Programmed according to Carrier defaults.
8. Duct Pressure set point established by user, or use fac-
tory default (1.50 in. wg).
VFD PROGRAMMING — To disable the supply fan motor
and change programming of VFD, perform the following:
1. Turn off Indoor Fan Circuit Breaker (IFCB). This will
remove power to the VFD.
2. Wait for the VFD display to go blank and remove VFD
cover without touching any interior components.
3. Ensure that the charge indicator lamp is out which
indicates that the VFD is discharged. The lamp is
located on the upper right-hand corner of the terminal
block. If still lit, wait until lamp goes completely out.
This may take several minutes.
4. Remove jumper from terminals ST-CC (see Fig. 49)
and replace VFD cover.
5. Turn on IFCB.
6. The drive output will now be disabled but the pro-
gramming can be changed.
7. Once the program changes are completed, turn off
IFCB.
8. Wait for the VFD display to go blank and remove VFD
cover without touching any interior components.
9. Ensure that the charge indicator lamp is out which
indicates that the VFD is discharged. The lamp is
located on the upper right-hand corner of the terminal
block. If still lit, wait until lamp goes completely out.
This may take several minutes.
10. Replace jumper to terminals ST-CC.
11. Replace VFD cover.
12. Turn on IFCB to enable the drive.
VFD OPERATIONAL STATUS — The VFDs contain ex-
tensive self-diagnostic functions which are accessed via the
VFD’s display panel (located on the front of the VFD or at a re-
mote location when the accessory remote display package has
been installed). See Fig. 50.
When power is first applied to the VFD, the display auto-
matically starts with the frequency monitor function of its
standard monitor mode. In the frequency monitor function, the
output frequency is displayed. Pushing the S/P/M key switches
to the mode selection menu. Pushing the S/P/M key again tog-
gles the display back to the standard monitor mode.
From the Mode Selection menu, the service person can
view all of the monitored status variables, including up to four
user-selected variables and any trip history in the memory.
Refer to the separate VFD Operation Manual included in
the installation packet for detailed instructions on accessing
diagnostic information, initiating troubleshooting, and clearing
any cleared trip history.
CARRIER FACTORY DEFAULT VALUES — The VFDs
have been specially programmed for use in Carrier units for
both general Carrier use and for the specific unit. Tables of
default values contained in the VFD Operation Manual includ-
ed in the installation packet will NOT APPLY to this unit. For
these specific models, refer to Appendix E for the VFD
defaults.
PRESSURE
(in. wg)
CONTROL
SIGNAL
(vdc)
PRESSURE
(in. wg)
CONTROL
SIGNAL
(vdc)
0.00
2.0
2.75
6.4
0.25
2.4
3.00
6.8
0.50
2.8
3.25
7.2
0.75
3.2
3.50
7.6
1.00
3.6
3.75
8.0
1.25
4.0
4.00
8.4
1.50
4.4
4.25
8.8
1.75
4.8
4.50
9.2
2.00
5.2
4.75
9.6
2.25
5.6
5.00
10.0
2.50
6.0
UNIT SIZES
ROTATION
JUMPER
034-048
Reverse
R-CC
054-074
Forward
F-CC
078-104
Forward
F-CC
If using the VFD’s front-mounted display panel, discon-
nect all power to the unit and the VFD before entering
unit, or use the accessory remote display module. Follow
instructions above for disabling supply fan and motor oper-
ation before accessing VFD-mounted display module.
P24 RES RR
F
R
S1
S2
S3
S4 RCH P24 LOW LOW
ST
FM AM CC
CC
RX
PP
IV
FP
FLC FLB FLA
REMOVE
JUMPER
Fig. 49 — Jumper Removal to Disable Motor
