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LED CODES AND SEQUENCE OF OPERATIONS
During start up, the LED will first display any error conditions (see table 12) if present. If no errors are detected then the LED
code indicating one or two stage operation will display then a long pause. The RPM indicator is displayed next. After the RPM
indicator is displayed there is a short pause and the sequence repeats if a thermostat demand is still present. See Figure 22
for LED sequence of operations. See table 13 for description of flash and pause durations.
Unit Status
Mismatched RPM
CRC Failure
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
YES
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Table 12. Error/Fault LED Codes
Table 13. Fan Motor Board Unit LED Codes
Unit Status
Low Stage
RPM Indicator
FAN MOTOR PWM CONTROL (ONE STAGE AND
MISMATCHED
RPM
CRC FAILURE
ECM1/Y1
SINGLE STAGE
ONLY OR
OR EDA
ECM2/Y2
OPERATION
ONLY
NO
DEMAND
ENDED
Figure 22. Single Stage LED Sequence of Operation
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Motor Control LED
Fast Flash with no pause
Constant ON.
ECM1/Y1 ONLY
SINGLE FAN SPEED)
DEFAULT FAN
MOTOR SPEED
LED CONTINUOUS FAST
USED
DEFAULT FAN
LED CONSTANT ON
MOTOR SPEED
USED
FAN MOTOR
RPM SET PER
JUMPER
SETTINGS
Page 43
Possible Cause
Internal feedback, PWM does not match tar-
get.
Microcontroller CRC failure.
Motor Control LED
One slow flash, then short pause.
Appropriate number of flashes (See Tables
11 and 2).
REPLACE FAN MOTOR
CONTROL BOARD
FLASH
REPLACE FAN MOTOR
CONTROL BOARD
STAGE LED INDICATOR: ONE
SLOW FLASH AND ONE
SHORT PAUSE FOR SINGLE
STAGE OR EDA OPERATION
LED RPM INDICATOR:
EXAMPLE: (2−TON
UNIT) – 5 SLOW
FLASHES AND ONE
LONG PAUSE
XC17 SERIES
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