Atlantic Boilers Error Codes

E01

Boiler does not ignite, burner does not start, display shows E01 shortly after a heating or hot water demand.

Ignition Failure / Flame Not Detected

E02

Boiler locks out with E02, burner stops shortly after ignition or during operation, sometimes accompanied by rumbling or popping noises.

Flame Loss During Operation

E03

Boiler attempts to start but shuts down with E03, fan may run briefly, no ignition noise heard.

Air Pressure Switch / Fan Combustion Circuit Fault

E04

Boiler stops and displays E04, often after running for a short time; casing may feel very hot, radiators may be partially warm.

Primary Circuit Overheat / Safety Thermostat Trip

E05

Boiler shows E05, will not start heating; may occur immediately on power-up or when a heating demand is present.

Flow Temperature Sensor (NTC) Fault

E06

Boiler displays E06, domestic hot water (DHW) may not function correctly or temperature fluctuates.

DHW Temperature Sensor (NTC) Fault

E07

Boiler locks out with E07, often associated with very high temperature readings or rapid cycling.

Return Temperature Sensor (NTC) Fault

E08

Boiler shows E08 and will not start; may be accompanied by low or zero pressure reading on the gauge.

Low Water Pressure / Pressure Switch Fault

E09

Boiler displays E09, may attempt to start but shuts down quickly; sometimes accompanied by unusual fan noise.

Fan Speed / Fan Feedback Fault

E10

Boiler shows E10 and stops; may occur during operation or at startup, often with gurgling noises in the boiler.

Insufficient Circulation / Flow Switch Fault

E11

Boiler displays E11, no hot water in combi mode, heating may still work.

DHW Flow Detection Fault

E12

Boiler shows E12, will not start; may be intermittent, often after power cuts or surges.

Control PCB Communication / Internal Error

E13

Boiler displays E13, may continue to run at reduced performance or shut down depending on model.

Flue Gas Temperature Sensor Fault / Overtemperature

E14

Boiler shows E14, often associated with frequent on/off cycling and unstable temperatures.

Modulation / Gas Valve Control Fault

E15

Boiler displays E15, may not respond to user inputs or may behave erratically.

User Interface / Keypad Fault

E16

Boiler shows E16, often related to external control issues; heating may not start even though the boiler appears powered.

Room Thermostat / External Control Fault

E17

Boiler displays E17, may be associated with very low return temperatures or cold radiators.

Condensing / Return Temperature Protection Fault

E18

Boiler shows E18, often during DHW operation, with very hot water or sudden shutdown.

DHW Overtemperature / Anti-Scald Protection

E19

Boiler displays E19, may not start or may shut down unexpectedly; sometimes after brownouts or unstable mains.

Power Supply / Low Voltage Fault

E20

Boiler shows E20, often associated with condensate issues or flue-related lockouts.

Condensate Drain / Siphon Fault

E21

Boiler displays E21, may be linked to incorrect sensor readings or inconsistent operation.

Sensor Calibration / Out-of-Range Fault

E22

Boiler shows E22, often when using advanced Atlantic controls or remote connectivity.

Communication Fault with External Module

E23

Boiler displays E23, may shut down or limit output; sometimes associated with sensor wiring damage.

Short Circuit on Sensor or Low-Voltage Circuit

E24

Boiler shows E24, often after overheating events or repeated lockouts.

Manual Reset Safety Thermostat Tripped

E25

Boiler displays E25, may be associated with incorrect configuration or incompatible accessories.

Configuration / Parameter Error

Symptom

Boiler does not start at all, no lights or display, as if completely dead.

No Power / Dead Boiler

Symptom

Boiler emits a burning smell or plastic smell during operation, with or without visible smoke.

Overheating Electrical Component

Symptom

Boiler flue terminal outside shows white staining or dripping water, and there may be damp patches on the wall near the flue.

Condensate / Flue Condensation Issue

Symptom

Boiler frequently loses pressure and needs to be topped up every few days, no visible leaks and no error code most of the time.

Chronic Pressure Loss

Symptom

Boiler frequently trips the electrical breaker or blows fuses when starting or during operation.

Electrical Short or Overload

Symptom

Boiler ignites with a loud bang or pop (delayed ignition) when starting.

Delayed Ignition

Symptom

Boiler is very noisy, with humming, grinding, or rattling sounds during operation, but continues to run.

Mechanical Noise / Vibration

Symptom

Boiler leaking water from underneath the casing or from pipe connections, no specific error code displayed.

Internal Water Leak

Symptom

Boiler makes loud banging or knocking noises (kettling) during operation, especially when heating starts or stops.

Kettling / Localized Boiling in Heat Exchanger

Symptom

Boiler runs but radiators remain cold or only lukewarm, while the boiler flow pipe is hot.

Poor Heating Circulation

Symptom

Boiler runs continuously and overheats the house even when the room thermostat is turned down or off.

Boiler Not Responding to Room Thermostat

Symptom

Boiler starts then shuts down after a few seconds without showing an error code, heating and hot water are unreliable.

Short Cycling / Unstable Operation

Symptom

Boiler works for heating but not for domestic hot water (or vice versa), with no error code displayed.

Diverter Valve / Hydraulic Selector Fault

Symptom

Domestic hot water temperature fluctuates between hot and cold during a shower, with no error code.

Inconsistent DHW Temperature