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MODGAS-X Technical Guide
LED Diagnostics
The MODGAS-X is equipped with LEDs that can be used to
verify operation and perform troubleshooting. There are LEDs
for communication, operation modes, and diagnostic codes. The
module has 10 LEDs—eight used for operation and status, and
two used for alarms. See
Figure 11, page 29
.
Operation LEDs
POWER
- This green LED will light up to indicate that 24 VAC
power has been applied to the MODGAS-X.
STATUS
- This green LED will light up and blink the board
address at startup. It will then blink every 10 seconds according
to the current mode. See
Table 6, this page
.
Diagnostic LEDs
ALARM
- This red LED located on the MODGAS-X cover above
the LCD display will light up to indicate an alarm. The type of
alarm(s) will be shown on the LCD display. The ALARM LED
also blinks when the expansion valve is initializing at startup.
The ALARM LED on the MODGAS-X will blink an alarm code
when an alarm(s) occurs. The highest priority failure code will
be indicated first. You must correct the highest priority alarm
before other problems will be indicated. See
Table 7, this page
.
Communication LED
COMM
- This yellow LED will light up and blink when
communications are detected.
Relay LEDs
RLY1
- This green LED will light up and stay lit as long as the
Fan Relay is active.
RLY2
- This green LED will light up and stay lit as long as the
Low Speed Fan Relay is active.
RLY3
- This green LED will light up and stay lit as long as the
Auxiliary Heat 1 Relay is active.
RLY4
- This green LED will light up and stay lit as long as the
Auxiliary Heat 2 Relay is active.
Binary Input LEDs
AUX BIN
- Not Used.
HEAT EN
- This green LED will light up when Heat is enabled.
No. of Blinks
STATUS LED
1
Off Mode
2
High Fire Mode
3
Heating Mode
4
Force Mode
Table 6: STATUS LED Blink Codes
No. of Blinks
ALARM LED
1
Mechanical Failure
2
Supply Air Temperature Sensor Failure
3
SAT Cutoff Mode
4
Communications Time Out Error
Table 7: STATUS LED Blink Codes
TROUBLESHOOTING
LED Diagnostics
