Lennox XC17 Series Unit Information page 42

Flash or Pause State
Flash Flash
Slow Flash
Short Pause
Long Pause
Unit Status
Mismatched RPM
CRC Failure
Table 14. One Stage
Model
XC17−024
XC17−030
XC17−036, −042
XC17−048, −060
* LED Code indicates Fan Motor Control LED flash sequence. For example, LED Code 9 indicates 9 slow flashes and pause.
Unit Status
One Stage Operation
RPM Indicator
NOTE There is a long pause between stage
operation and RPM indicator. See tables 1 and 2
for LED RPM indicator.
Flash Flash = Three flashes per second.
Slow Flash = One flash per second.
Short Pause = Two seconds of OFF time.
Long Pause = Five seconds of OFF time.
DEMAND
BEGINS
MISMATCHED
RPM
CRC FAILURE
SINGLE STAGE
OR EDA
OPERATION
YES
NO
DEMAND
ENDED
Figure 20. Fan Motor Control One Stage LED Sequence of Operation
XC17
Table 12. Fan Motor Control Flash and Pause Durations
Table 13. Fan Motor Control (A177) Error/Fault LED Codes
Fan Motor Control LED
Fast Flash with no pause
Fan Motor Control RPM Jumper Settings, LED RPM Indicator and P2 DC Voltage Outputs
CFM Profile Pin Select
4 3
OFF ON
OFF ON
OFF OFF
OFF OFF
Table 15. Fan Motor Control Unit LED Codes
Unit Status
Low Stage
RPM Indicator
DEFAULT FAN
MOTOR SPEED
USED
DEFAULT FAN
MOTOR SPEED
USED
ECM1/Y1
ONLY OR
ECM2/Y2
ONLY
Internal feedback, PWM does not match target.
Constant ON. Microcontroller CRC failure.
2 1
ON ON
ON OFF
ON ON
OFF ON
ECM1/Y1 ONLY
LED CONTINUOUS FAST
FLASH
LED CONSTANT ON
FAN MOTOR
RPM SET PER
JUMPER
SETTINGS
Page 42
Duration
Three flashes per second
One flash per second
Two seconds of OFF time.
Five seconds of OFF time.
Possible Cause
ECM1/Y1
RPM (J2) DC Volt
400 12.7
450 14.3
600 19.2
675 21.6
Fan Motor Control LED
One slow flash, then short pause.
Appropriate number of flashes (see tables
14).
REPLACE FAN MOTOR
CONTROL BOARD
REPLACE FAN MOTOR
CONTROL BOARD
STAGE LED INDICATOR: ONE
SLOW FLASH AND ONE
SHORT PAUSE FOR SINGLE
STAGE OR EDA OPERATION
UNIT) – 5 SLOW
FLASHES AND ONE
LED RPM INDICATOR:
EXAMPLE: (2−TON
LONG PAUSE
LED Code*
5
6
8
9