BoilerFaultCodes 1 flash green
Temperature protection: Maximum flow temperature exceeded, Flow temperature rise rate too high, Excessive difference between flow and return temperature
Baxi EcoBlue 21 Heat ErP Fault codes & diagnostics
12 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Gas 2014-present
GC Number 41-470-32
Download the Baxi EcoBlue 21 Heat ErP manual
PDF
Versions & GC numbers
This boiler uses LED flash patterns
Count the flashes in one repeating group before the pause. That number is your fault code. Do not reset until you have noted it. How to read fault codes →
Severity at a glance
Each cell = one fault code. Hover to identify. 12 Unrated
Which version do you have?
The GC number on your boiler's data badge identifies the exact appliance and production years, as recorded in the UK Product Characteristics Database.
| GC number | Appliance (register name) | Produced |
|---|---|---|
| 41-470-32 | EcoBlue 21 Heat ErP | 2014–present |
Appliance names and production years are taken from the UK Product Characteristics Database (the SAP/SEDBUK register). Where a GC number is also printed in this model's own manufacturer manual, both sources were checked to agree.
Just want the most common Baxi EcoBlue 21 Heat ErP faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes
All 12 documented codes
Tap any card for details
1 flash red
Sensor error: Bad connection to flow or return temperature sensor, Fault with flow or return temperature sensor(s), Low or no flow through boiler, Reverse flow through boiler
2 flashes green
Shutdown input: BL terminals on User Interaction Controller are open circuit
2 flashes red
High temperature protection: Over-temperature thermostat on heat exchanger activated, No water flow through heat exchanger, Over-temperature thermostat fault or bad connection (open circuit), PCB over-temperature condition, Flue fault resulting in recirculation or activation of air pressure switch (if fitted)
3 flashes green
Flame loss: No flame detected during operation
3 flashes red
Ignition fault: No ignition, No flame detected following ignition, False flame signal detected, Repeated loss of flame detected
4 flashes green
Communication fault: Bad connection or wiring fault, Internal communication fault
4 flashes red
Fan fault: Fan calibration error, Fan failure
5 flashes green
Parameter fault: Parameter error or faulty PU, Configuration error or PCB fault
5 flashes red
Parameter fault: Bad connection to PU, Parameter error or faulty PU
6 flashes green
Miscellaneous: Internal fault in combustion control unit
6 flashes red
Miscellaneous: Bad connection or wiring fault internal or external to the boiler, Parameter error, Communication error
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