Bryant 548J - VFD BYPASS AND PARAMETERS; Bypass the VFD

33
Fig. 50 — Remove Fan from Holder
Bypass the VFD
The factory-installed VFD is wired and agency approved as out-
lined in this manual. This VFD is utilized to help provide added
efficiencies and comfort during the cooling operation.
If there is an occasion where the VFD has mis-functioned and
temporary cooling/operation is required, bypass the VFD as
shown in Fig. 51 and 52.
To bypass ACS320 VFD on fused units – 580J/558J*07-14,
548J 07-12, 581J/551J*07-12, 549J*08-09, and 524J:
1. Turn off and lock out unit power.
2. Disconnect the connector linking the fuse to the VFD.
3. Disconnect the connector between the VFD and the indoor
fan motor.
4. Disconnect the ground wires at the base of the VFD.
5. Remove the VFD, if required.
6. Replace standard fuses with Slow Blow fuses.
7. Connect the lead from the fuse to the lead from the indoor fan
motor.
8. Connect the ground wire from the indoor fan motor to the fan
deck.
9. Restore power.
To bypass ACH550/580 VFD on non-fused units –
580J/558J*16-30, 548J*14-24, and 581J/551J*17-28:
1. Turn off and lock out unit power.
2. Disconnect the connection between the control box and the
VFD.
3. Disconnect the connection between the indoor fan motor and
the VFD.
4. Disconnect the ground wires at the base of the VFD.
5. Remove the VFD, if required.
6. Connect the lead from the control box to the lead from the
indoor fan motor.
7. Attach the ground wire leading from the fan motor to the fan
deck.
8. Restore power.
NOTE: Standard fuses need to be replaced with Slow Blow fuses for bypass.
Fig. 51 — To Bypass ACS320 VFD on Fused Units —
580J/558J*07-14, 548J*07-12, 581J/551J*07-12, 549J*08-09 and 524J Units
Fig. 52 — To Bypass ACH550/580 VFD on Non-fused Units —
580J/558J*16-30, 548J*14-24 and 581J/551J*17-28 Units
WARNING
Bypassing the VFD is not recommended. This is a temporary
procedure to provide cooling or heating operation when a new
VFD is required. When in this bypass mode the fire shut down
will not turn off the blower and it will continue to run. The
bypass should only be used for a short duration until a new
VFD has been received.
7
6
6
6
Control
Box
Ground
Fuse
VFD
Unit with Fuse and VFD
Unit without VFD
Control
Box
Ground
Fuse
Fan Deck
Fan Deck
Indoor
Fan
Motor
Indoor
Fan
Motor
Indoor
Fan
Motor
Indoor
Fan
Motor
ACH550/
ACH580
VFD
Fan Deck
Fan Deck
Control
Box
Ground
Unit with VFD
Unit without VFD
Control
Box
Ground