Bryant FA4A - Manual (Page 18)

A U G / 1 4 / 2 0 0 8 / T H U 0 3 : 4 9 UTC TECH PUB 1 , 3 1 7 2 4 0 5 6 6 2 P , 0 1 8
A
CAUTION: Disconnect elfictdcd power before remov-
Щ any access panels.
FF1A/FF1B SERVICE AND TROUBLESHOOTING
To clean blower motor or blower wheel:
1. Remove blower access panel.
2. Remove motor leads from PCB. Note lead loofttion for case
of reassembly.
3. Remove 2 outside screws holding blower/jiiotor assembly
against blower-deck flange and slide assembly out of
cabinet,
4. Remove screw in strap holding motor capacitor to blower
housing and slide capacitor Out from under strap. Remove
screw with green wire from blower housing. Mafic blower
wheelj motor, and motor support in relation to blower
housing before disassembly to ensure proper reassembly.
Note position of blades on wheel,
5. Loosen setscrew holding blower wheel onto motor shaft,
6. Remove 3 bolts holding motor mount to blower housing and
slide motor and mount out of housing. Further disassembly
should not be necessary as adequate clearance is available.
7. Remove blower wheel from housing by removing cutoff
plate from blower housing outlet. Note wheel orientation
and cutoff location for reassembly. The blower motor and
wheel may be cleaned by using a vacuum With a soft-brush
attachment.
S. Remove grease with a mild solvent such as hot water and
detergent. Be careful not to disturb balance weights (clips)
on blower-wheel vanes. Also, do not drop or bend wheel, as
balance will be affected.
To reassemble blower:
f. Place blower wheel back into housing. Be sure to position
correctly for proper location.
2. Reassemble cutoff plate to housing using identified holes
disassembly procedure.
3. Position motor and mount in same position as when blower
housing was in unit. Secure motor mount on housing, using
removed bolts. Make sure mount or motor is grounded to.
blower hoiising.
4. Locate blower wheel setscrew over flat on motor shaft.
Rotate wheel in housing. It should not mb housing and
should be centered in inlet opening. If notj loosen setscrew
and align as necessary.
5. Attach green wire to blower housing with screw.
6. Secure motor capacitor under strap and tighten strap screw.
7. Slide blower assembly to blower deck. Be sure (once
blower is within the unit casing) to force blower assembly
toward control box while sliding assembly into unit to
ensure that blower assembly engages deck properly.
8. Fasten blower assembly to deck with screws previously
removed.
9. Reconnect electrical leads to PCB.
10. Reconnect electrical power to unit and test fan for proper
rotation.
WARNING: Before installation or servicing system,
always turn off main power to system: There may be
more than 1 disconnect switch. Turn off accessory heater
power if applicable. Electrical shock can cause personal
injury or death.
L FAN MOTOR
The motor is 2-spccd direct drive. High-speed lead is black,
low-speed lead is red, and common lead is violet. Be sure proper
blower speed has Ьeí^п selected. For units with electrical heat,
low-speed tap can be used. For cooling, use high-speed tap.
The motor is turned on through 2 different routes. The first occurs
when thermostat calls for the fan in cooling, heat pump, or
fan-only mode, A 24-vac signal is sent to relay, causing relay to
dose its normally-open contacts, turning fan on. The second
occurs when there is a call for electric heat. A 24-vac signal is sent
to heater sequencer, causing it to dose, directing 230v through the
normally-closed contact of fan relay, turning fan on. The fan
remains on until sequencer opens. Refer to FFIA/FFIB typical
wiring diagram Shown in Fig. 16.
If motor docs ПШ, test motor for an open winding or a winding
shorted to motor case. If any 1 of the 2 is present, replace motor.
II. ELECTRIC HEATER SERVICE
Service can be completed with heater in place. Shut off power
before servicing,
A. Limit Switch
Malfunction prevenís heating element from coming on. Replace
switch if malfunction occurs.
B. Sequencer
Malfunction causes heater not to come on or never shut off.
Replace sequencer. '
C. Transformer
A 40-va transformer supplies 24-v power for control circuit.
Replace transformer if faulty,
NOTE: Transformer is fused. Do not short circuit.
D. Fan Relay
Malfunction causes unit fan not to run Or run continuously.
Replace relay.
III. CLEANING OR REPLACING REFRIGERANT FLOW-
CONTROL DEVICE
Refer to Fig. 13 and instructions given in Piston Body Cleaning or
Replacement section above,
IV. LIQUID TUBE STRAINER
The refrigerant flow-control device is protected by a wire mesh
strainer. It is located inside the З/8-Ín. liquid tube at field braze
joint next to flow-control device. Access to strainer is through field
braze joint.
V. SEQUENCE OF OPERATION
Refer to Fig, 16,
A. Condensing Unit
COOLING
When thermostat calls for cooling, the circuit between R and G is
complete and single-pole single-throw relay FR is energized. The
nomially-open contacts close causing blower to operate. The
circuit between R and Y is also complete. This completed circuit
causes contactor in outdoor unit to close which starts compressor
and outdoor fan.
-18^