Search my own database of fault, diagnostic and status codes to aid in fault identification.
This is an open circuit issue within the NTC circuit, check the NTC or the cable harness connecting the NTC.
Short circuit of the flow temperature sensor.
Appliance temperature has exceeded the maximum value and needs to cool down.
No water or flow in system. Possible pump or, on these models, the pump lead may have failed.
Pump could be lame, blocked or not running. Another common reason can be trapped air in the appliance preventing flow.
Check the gas supply, ignition, gas valve or lead.
Possibly fan or gas valve issues. Flue issues can also cause this problem.
Short circuit issues in the loom or the gas valve itself is a common issue here.
Open circuit issues within the loom or gas valve itself.
Possibly the gas valve is not shutting down in time causing the boiler to detect additional temperature rises when not expected.
New PCB
PCB, harness or NTC issue.
Likely that the PCB has started to break down, however this can also be caused by external heat sources warming the appliance up beyond it's working parameters.
