8.2.4 Aux. Interlock 1 or 2
Aux. Interlock 1 or 2
Issue Diagnosis Fix
Interlock 1 or 2
terminals are open.
Jumper lead is loose
or compromised.
Replace the jumper lead.
External safety is in an
alarm state.
Inspect the external safety devices.
8.3 Miscellaneous touchscreen controller errors
Miscellaneous errors
Issue Diagnosis Fix
“Loop/Indoor Sensor”
“Insufficient Air Flow”
“Insufficient Water
Pressure”
The sensor plug is not
engaged.
Check the P501 plug is fully engaged in the
back of the controller board.
“Unknown Error” The sensor plug is not
engaged.
Check the P501 plug is fully engaged in the
back of the controller board.
Temperature sensor
input problem.
Test each temperature sensor for appropriate
readings and Replace defective temperature
sensor.
Error - Max.
Inlet/Outlet Sensor
Temp. Exceeded. >
Check water flow
Water temperature
signal not within
acceptable range.
Potential flow or
sensor failure. Consult
service technician.
Current outlet
temperature exceeds
operating limit.
Check water flow.
Defective or
disconnected
temperature sensor.
Check wiring to temperature sensor and
control module.
Check temperature sensor.
Blank – screen dark,
but fan running
Indicative of power-
surge damage to
appliance
Check transformer; replace if damaged.
Check circuit board for visible damage.
Controller is stuck in
If update fails or no Restarting returns the boiler to normal
8.2.4 Aux. Interlock 1 or 2