Lennox XP16 Series Unit Information page 43

The DC filter capacitors inside the controller are connected
electrically to the speed tap wires. The capacitors take
approximately 5 minutes to discharge when the disconnect
is opened. For this reason it is necessary to wait at least 5
minutes after turning off power to the unit before attempting
to service motor.
DANGER
Disconnect power from unit and wait at
least five minutes to allow capacitors
to discharge before attempting to ser-
vice motor. Failure to wait may cause
personal injury or death.
Motor Start-Up
At start-up, the motor may gently rock back and forth for a
moment. This is normal. During this time the electronic
controller is determining the exact position of the rotor.
Once the motor begins turning, the controller slowly eases
the motor up to speed (this is called soft-start"). The motor
may take as long as 10-15 seconds to reach full speed. If
the motor does not reach 200 rpm within 13 seconds, the
motor shuts down. Then the motor will immediately
attempt a restart. The shutdown feature provides
protection in case of a frozen bearing or blocked fan blade.
The motor may attempt to start eight times. If the motor
does not start after the eighth try, the controller locks out.
Reset controller by momentarily turning off power to unit.
Troubleshooting
If first or second stage thermostat call for cool is present and
the variable speed condenser fan motor does not energize,
check voltage at the breaker box. If voltage is present
perfrom the following steps and refer to figure 28.
1. Check for 240 volts between the compressor RED
wires.
2. nitiate a first stage call for cool. Check for 24 volts
between the fan motor YELLOW wire and fan motor
BLACK wire.
FAN BLADE HUB (BOTTOM)
XP16
MOTOR
MOTOR SHAFT
Figure 29. Fan Blade Mounting Position on Motor Shaft
Page 43
3. Initiate a second stage call for cool. Check for 24 volts
between the fan motor YELLOW wire and fan motor
BLACK wire, then check for 24 volts between the fan
motor BLUE wire and fan motor BLACK.
4. Repeat steps 1 and 2 with a HEAT call.
1st Stage (low capacity − 700 rpm)
RED
RED
YELLOW
BLUE
B4
BLACK
common
2nd Stage (High capacity − 820 rpm)
RED
RED
YELLOW
BLUE
B4
BLACK
Figure 28. Speed Taps for PSC Fan Motors
Replacement
Flush mounting indicates to mount it at the end of the shaft so
that the bottom of the fan blade hub is flush with the end of
the motor shaft. Dimension A would be 0 (flush). Torque set
screw between 137 − 150 in. lbs (approximately 1/8th turn
using a standard socket and wrench).
Table 6. Mounting on Shaft
XP16 UNIT
−024, −036
−048, −060
−060*
*XP16−060−230−05 only
0
A
240V
240V
Y1
24V
Y2
0V
24V
240V
240V
Y1
24V
Y2
24V
common 24V
"A" DIM. + 1/8"
3/4" (19mm)
Flush
1−7/8" (47.5mm)
1/8 TURN
11 12
1
2
10
9 3
4
8
5
7
6