hot water and detergent. Be careful not to disturb balance weights
(clips) on blower wheel vanes. Do not drop or bend wheel as
balance will be affected.
FG3A SERVICE AND TROUBLESHOOTING
Step 1—Service
MOTOR
Ball bearing oilers are provided on blower motor. Use electric
motor oil or SAE 10 or 20 nondetergent oil. Check motor mount
bracket and base bolts. Tighten as required.
BLOWER
Check ball bearings for wear. Ball bearings are self-aligning and
grease packed. Replace as required. Check thrust collars for end
play and alignment of wheel. Check blades for accumulation of
dirt. Clean as required. Check mounting brackets, base bolts, and
isolation material.
See Fig. 37 for diagram of internal wiring for blower coil
assembly. Control box (standard 4-in. junction box) is mounted on
refrigerant connection side of unit. All leads pass through strain
relief where they enter control box. Wiring inside cabinet is
located so it does not come in contact with moving parts or sharp
edges.
PULLEY AND BELTS
Check belt tension and pulley alignment. (See Fig. 38.) Belt
tension is adjusted by motor tailpiece bolt. A deflection of about
3/4 in. to 1 in. per foot of span should be obtained by pressing belt
firmly. Lock adjusting bolt in position after adjustment is made.
Align pulley grooves by locating motor pulley on motor shaft or by
moving entire motor along motor mounting bracket. Adjust blower
speed by loosening setscrew in outer (moveable) pulley face and
turning this face (half or full turns) so that adjusting setscrew is
positioned precisely over the flat on pulley hub. Speed is reduced
by adjusting pulley faces so they are further apart; speed is
increased with faces closer together. Check pulley setscrews and
bolts.
CLEANING OR REPLACING REFRIGERANT
FLOW-CONTROL DEVICE
Refer to Fig. 36 and instructions given in FD3A Service and
Troubleshooting section above.
Step 2—Maintenance
Disconnect electrical power to all circuits before servicing
unit. Failure to do so may result in personal injury from
electrical shock or moving parts.
As with any mechanical equipment, personal injury can result
from sharp metal edges. Be careful when removing parts.
RETURN-AIR FILTER
To clean or replace air filter, remove screws and filter access door.
Slide out filter. For washable type filters, clean with hot soapy
water. Rinse clean and let dry.
New filters are available from a local distributor. Place filter in slot
with filter arrow facing direction of airflow. Replace filter access
doors with screws previously removed.
Never operate unit without a filter or with filter access door
removed. Damage to blower motor may result.
COIL, DRAIN PAN, AND CONDENSATE DRAIN
Disconnect electrical power before removing any access
panels or electrical shock may result.
The coil is easily cleaned when dry. To check or clean coil, remove
coil access panel. If coil is coated with dirt or lint, vacuum with a
soft brush attachment.
Be careful not to bend fins. If coil is coated with oil or grease, it
may be cleaned with mild detergent and water solution. Rinse coil
with clean water. Be careful not to splash water on insulation or
filter.
Check drain pan and condensate drain at same time cooling coil is
checked. Clean drain pan and condensate drain by removing any
foreign matter from pan. Check for rust and holes. Flush pan and
drain tube with clear water. If drain is restricted, clean with
high-pressure water. If this does not work, use a plumber’s snake
or similar probe device. Repitch drain pan to promote proper
drainage.
FA4A, FB4A, FC4B, AND FX4A SMART HEAT
CIRCUIT BOARD FUNCTION AND TROUBLESHOOTING
Step 1—PCB Component Layout, Description,
and Function
NOTE:
All voltages are AC unless otherwise specified.
1. The low-voltage terminal board is used to connect indoor
thermostat to low, 24-v side of transformer and to serve as a
junction between indoor thermostat and outdoor section.
a. R terminal is used to connect secondary side of transformer
to thermostat and outdoor unit. R is fused.
b. C terminal is used to connect transformer secondary
common for thermostat and outdoor unit.
c. Y terminal provides input signal from thermostat signaling
heat pump operation.
Fig. 37—Wiring Schematic
A91151
BLOWER
MOTOR
GROUND
UTILITY
BOX
GROUND
LEAD
LINE
Fig. 38—Checking Pulley Alignment and Tightness
A91150
1
′
3
⁄
4
″
BELT ADJUSTMENT
PULLEY ALIGNMENT
MUST BE
PARALLEL
FOR PROPER
ALIGNMENT
46
