Commercial Air Conditioner
Model: heat pump, 10SEER UNITS
35
Run capacitor
Fig.10-2
Some compressor require the assistance of an additional potential relay to start. The potential relay
connect to the contactor. The potential use two terminals:5 and 2 ;The relay coil that opens them is
between terminal 2 and 5
START KIT ELECTRICAL CHECKS
WARNING:DISCONNECT ALL POWER TO THE OUTDOOR UNIT BEFORE BEGINNING THIS
TEST
.
MOTORS
ELECTRICAL
The motors in both the outdoor unit and indoor unit are similar .Outdoor motors have one speed while
indoor unit usually are multi-speed. All fan motors require a capacitor for the best torque and efficiency.
If
the motor is replaced,
replace the capacitor.
The fan motor has both “Run” and “Start “windings .Extended run windings furnish a choice of speeds
with indoor products. Use an Ohmmeter to troubleshooting motors.
Indicator
Fig.10-3
ELECTRICAL CHECKS
1. Be sure power is off to the motor.
2. Disconnect the motor wires.
3. Place one ohmmeter lead on
common
and the other on
start
.The meter should show continuity.
4. Place one ohmmeter lead on
common
and the other on
run
. The meter should show continuity with
less resistance.
5. Leave one meter lead on
c
ommon
and touch each remaining lead. Each should indicate continuity.
6. If a winding does not show continuity, the motor has failed and must be replaced.
7. If the motor needs replacing, replace the capacitor as well.
MECHANICAL
Fan motors can suffer a bearing loss due to a lack of lubrication .This may be caused by excessive water spilling
from a roof above the unit. Lubrication can be washed out of permanently lubrication causes dirt to stick to oiling
ports and can contaminate the bearings. If a motor fails, replace it with another having the same rotation and
