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.
Table 12. Error/Fault LED Codes
Unit Status | Motor Control LED | Possible Cause | |
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Mismatched RPM | Fast Flash with no pause | Internal feedback, PWM does not match tar- | |
get. | |||
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CRC Failure | Constant ON. | Microcontroller CRC failure. | |
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Table 13. Fan Motor Board Unit LED Codes
Unit Status | Unit Status | Motor Control LED | |
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One Stage Operation | Low Stage Y | One slow flash, then short pause. | |
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RPM Indicator |
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NOTE There is a long pause between stage | RPM Indicator | Appropriate number of flashes (See Tables | |
operation and RPM indicator. See Tables 1 and 2 | 11 and 2). | ||
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for LED RPM indicator. |
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Flash Flash = Three flashes per second. |
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Slow Flash = One flash per second. |
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Short Pause = Two seconds of OFF time. |
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Long Pause = Five seconds of OFF time. |
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DEMAND BEGINS
FAN MOTOR PWM CONTROL (ONE STAGE AND SINGLE FAN SPEED)
MISMATCHED
RPM
CRC FAILURE
DEFAULT FAN MOTOR SPEED
USED
DEFAULT FAN MOTOR SPEED USED
LED CONTINUOUS FAST
FLASH
LED CONSTANT ON
REPLACE FAN MOTOR CONTROL BOARD
REPLACE FAN MOTOR CONTROL BOARD
YES
SINGLE STAGE
OR EDA
OPERATION
NO
DEMAND
ENDED
ECM1/Y1
ONLY OR ECM2/Y2
ONLY
FAN MOTOR RPM SET PER JUMPER SETTINGS
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
Figure 22. Single Stage LED Sequence of Operation
Page 43
XC17 SERIES