73
13 - TROUBLE SHOOTING
Troubleshooting Chart 1
E02 - Supply Sensor Short
E03 - Supply Sensor Open
E04 - Heat Exchanger Temp.
E05 - Heat Exchanger Temp.
E06 - Return Sensor Short
E07 - Return Sensor Open
E08 - Low Return Temp.
E09 -High Return Temp.
Locate Appropriate Sensor
See Figure 1 (page) and
Figure (Wire Diagram)
Trace wire leads. Are all
connections tight and wires
undamaged?
NO
YES
Check continuity across
sensor.
OK?
NO
YES
Repair wire
and/or fix
connection.
Check sensor element is
properly installed in pipe.
NO
YES
Replace
Sensor
Replace
Control Board
Re-Install
Sensor Properly
Check sensor resistance
and compare to
temperature resistance
curve (Figure 13-1 page
87. (Remove sensor if
needed). OK?
NO
YES
Replace
Sensor
Note
DOMESTIC HOT WATER SENSOR: If the DHW sensor is shorted it will act as a closed thermostat and boiler will
continuously fire.
PN 240011664, Rev. L [11/01/2020]
