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MODGAS-XWR2-B Technical Guide
TROUBLESHOOTING
LED Diagnostics
LED Diagnostics
The MODGAS-XWR2-B 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 14 LEDs—12 used for operation and status, and two
used for alarms. (
Figure 16, page 37
).
Operation LEDs
POWER:
This green LED will light up to indicate that 24 VAC
power has been applied to the module.
STATUS:
This green LED blinks every five seconds according to
what mode the module is in. See
Table 5, this page
.
Diagnostic LEDs
ALARM:
This red LED located on the MODGAS-XWR2-B 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-XWR2-B 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 6, 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 Heat
Enable 1 relay is active.
RLY4:
This green LED will light up and stay lit as long as the Heat
Enable 2 relay is active.
RLY5:
This green LED will light up and stay lit as long as the Heat
Enable 3 relay is active.
RLY6:
This green LED will light up and stay lit as long as the Heat
Enable 4 relay is active.
Binary Input LEDs
AUX BIN:
Not Used.
HEAT EN:
This green LED will light up when Heat Enable signal
is activated.
PO-IGN1:
This green LED will light up when the Proof of Flame
input from the first ignition module is enabled.
PO-IGN2:
This green LED will light up when the Proof of Flame
input from the second ignition module is enabled.
Analog Output LEDs
GAS VALVE 1 and GAS VALVE 2:
These red LEDs will do the
following:
• If the valve is detected and not modulating, then the valve
LED is solid.
• If the valve is modulating, then it will blink while it is
moving.
• If the valve is not detected, the valve LED will continuously
blink.
• If there shouldn’t be a modulating valve attached to the
valve header, then the valve LED remains off.
No. of Blinks
STATUS LED
1
Off Mode
2
Heating Mode
(Heat Enable Signal and No Alarms)
Table 5: STATUS LED Blink Codes
No. of Blinks
ALARM LED
1
Valve 1 Proof of Flame Failure
2
Valve 1 Not Detected
3
Valve 2 Proof of Flame Failure
4
Valve 2 Not Detected
5
SAT Not Detected (Stand-Alone Mode)
6
SAT Cutoff
7
Relay 12 Communication Failure
8
Communication Failure
9
Stage 1 Failure
10
Stage 2 Failure
Table 6: ALARM LED Blink Codes
