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7.10 FAULT CODES
When the boiler detects a temporary fault condition, the
appropriate code is shown flashing on the display. If/when
the fault code is final, the pump will perform a 60-second
post circulation and the red LED will be illuminated.
CODE
CAUSE
ALARM TYPE
ACTION
AL10
Ignition failure/not flame sensed,
Final
Reset, check appliance operation
condense sensor activated
AL20
Limit thermostat fault
Final
Reset, check appliance operation
AL21
External device fault (UHT/CPA)
Final
Reset, check appliance
AL26
Return temperature too high
Final
Reset, check pump, ensure there is sufficient
flow sensor temperature). circulation around
heating circuit/s
AL28
Temperature differential inverted
Final
Reset, check pump, ensure there is sufficient
(return sensor temperature higher than
circulation around heating circuit/s thermistors
flowsensor temperature)
AL34
Fan tacho signal fault
Final
Reset check appliance operation, check fan
AL52
Internal fault
Final
Reset, check appliance operation
A
L55
Jumper tag fault
Final
Check jumper tag configuration
AL60
Jumper tag fault
Temporary
Check jumper tag configuration
AL71
Primary (flow) thermistor fault
Temporary
Check primary thermistor, check wiring
AL73
Return thermistor fault
Temporary
Check return thermistor, check /wiring
AL74
No water circulation
Final
Reset, check appliance operation, check
pump, ensure there is water and sufficient
circulation around heating circuit/s
AL79
Flow temperature too high, or
Final
Reset, check appliance operation, check
temperature differential between
thermistors
primary and return too high