Nibe
Nibe Water Heaters Error Codes
Complete list of fault codes and troubleshooting guides. Use the search below to find your specific error.
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A01
Water heater will not start; display shows A01 and unit remains in standby despite heat demand.
High-Temperature Safety Trip (Manual Reset Thermostat Activated)
A02
Display shows A02 and water heater stops heating; unit indicates overheat in tank sensor.
Tank Temperature Sensor Overheat / Sensor Fault
A03
Display shows A03; water heater stops and may show message related to low water level or dry fire protection.
Dry-Fire / Low Water Level Protection Activated
A04
Display shows A04; water heater does not heat and indicates sensor fault for hot water.
Domestic Hot Water Sensor Fault
A05
Display shows A05; water heater stops and may indicate return temperature sensor fault.
Return Temperature Sensor Fault
A06
Display shows A06; water heater indicates flow temperature sensor fault and may limit output.
Flow Temperature Sensor Fault
A07
Display shows A07; water heater may shut down and indicate outdoor sensor fault (for systems using outdoor compensation).
Outdoor Temperature Sensor Fault
A08
Display shows A08; water heater indicates communication error with external heat source or accessory.
Communication Fault with External Unit (e.g. Heat Pump or Control Module)
A09
Display shows A09; water heater indicates circulation pump fault and may stop heating.
Circulation Pump Failure or Blockage
A10
Display shows A10; water heater indicates electric heater fault and may disable immersion heating.
Immersion Heater / Electric Element Fault
A11
Display shows A11; water heater indicates high pressure or safety valve activation.
Overpressure in Cylinder / Safety Valve Activation
A12
Display shows A12; water heater indicates low pressure in heating circuit (for indirect systems).
Low System Pressure in Primary Heating Circuit
A13
Display shows A13; water heater indicates sensor fault on solar coil or additional heat source coil.
Auxiliary Coil Temperature Sensor Fault
A14
Display shows A14; water heater indicates legionella protection fault or failed high-temperature cycle.
Legionella Protection Cycle Failure
A15
Display shows A15; water heater indicates internal control fault or EEPROM error.
Control Board Internal Error
A16
Display shows A16; water heater indicates sensor short-circuit or overrange on one of the NTC inputs.
Generic NTC Sensor Short-Circuit
A17
Display shows A17; water heater indicates sensor open-circuit or underrange on one of the NTC inputs.
Generic NTC Sensor Open-Circuit
A18
Display shows A18; water heater indicates flow switch fault or no flow detected when pump is running.
Flow Switch / Flow Sensor Fault
A19
Display shows A19; water heater indicates sensor fault on cold water inlet or mixing valve sensor (if equipped).
Cold Inlet / Mixing Valve Sensor Fault
A20
Display shows A20; water heater indicates maximum runtime exceeded for heater or pump.
Maximum Runtime / Overrun Protection
Symptom
Hot water has a metallic or rusty color when first drawn from taps connected to the Nibe water heater.
Internal Corrosion / Anode Depletion
Symptom
Hot water has a rotten egg or sulfur smell when using taps supplied by the Nibe water heater.
Bacterial Growth / Sulfide Reaction in Cylinder
Symptom
Hot water runs out very quickly; initial water is hot but becomes cold after a short time.
Reduced Effective Storage Volume / Stratification Problem
Symptom
Water heater causes noticeable vibration in nearby pipework and structure during operation.
Hydraulic Vibration / Water Hammer
Symptom
Water heater connected to a Nibe heat pump does not receive heat; coil connections remain cold while heat pump runs.
No Heat Transfer from External Heat Source
Symptom
Water heater cycles on and off rapidly, with short heating periods and frequent restarts.
Short Cycling / Control Instability
Symptom
Water heater display is on but buttons or touch controls do not respond.
User Interface / Keypad Failure
Symptom
Water heater does not start after a power outage; display is blank or unresponsive.
No Power / Control Panel Failure
Symptom
Water heater emits a humming or buzzing noise from the circulation pump area.
Circulation Pump Noise / Partial Seizure
Symptom
Water heater frequently drips water from the safety valve discharge pipe.
Frequent Safety Valve Discharge
Symptom
Water heater is leaking from the bottom or around connections; puddles form under the Nibe cylinder.
Water Leak from Cylinder or Fittings
Symptom
Water heater makes loud banging or knocking noises when heating.
Kettling / Boiling Noise Due to Scale or Local Overheating
Symptom
Water heater produces no hot water at all; taps run cold despite power being available.
Complete Loss of Heating Function
Symptom
Water heater provides only lukewarm water; temperature at taps is lower than setpoint and drops quickly.
Insufficient Hot Water Temperature / Capacity
Symptom
Water heater trips the electrical breaker or RCD when heating starts.
Electrical Short or Earth Leakage from Heater
Symptom
Water heater’s external casing is unusually hot to the touch and heat loss seems high.
Insulation Degradation / Heat Loss
Symptom
Water heater’s hot water temperature fluctuates significantly during a single shower.
Unstable Outlet Temperature / Mixing Valve or Control Issue
| Error Code | Symptom | Fault Type | Guide |
|---|---|---|---|
| A01 |
Water heater will not start; display shows A01 and unit remains in standby despite heat demand.
|
High-Temperature Safety Trip (Manual Reset Thermostat Activated) | View Details |
| A02 |
Display shows A02 and water heater stops heating; unit indicates overheat in tank sensor.
|
Tank Temperature Sensor Overheat / Sensor Fault | View Details |
| A03 |
Display shows A03; water heater stops and may show message related to low water level or dry fire protection.
|
Dry-Fire / Low Water Level Protection Activated | View Details |
| A04 |
Display shows A04; water heater does not heat and indicates sensor fault for hot water.
|
Domestic Hot Water Sensor Fault | View Details |
| A05 |
Display shows A05; water heater stops and may indicate return temperature sensor fault.
|
Return Temperature Sensor Fault | View Details |
| A06 |
Display shows A06; water heater indicates flow temperature sensor fault and may limit output.
|
Flow Temperature Sensor Fault | View Details |
| A07 |
Display shows A07; water heater may shut down and indicate outdoor sensor fault (for systems using outdoor compensation).
|
Outdoor Temperature Sensor Fault | View Details |
| A08 |
Display shows A08; water heater indicates communication error with external heat source or accessory.
|
Communication Fault with External Unit (e.g. Heat Pump or Control Module) | View Details |
| A09 |
Display shows A09; water heater indicates circulation pump fault and may stop heating.
|
Circulation Pump Failure or Blockage | View Details |
| A10 |
Display shows A10; water heater indicates electric heater fault and may disable immersion heating.
|
Immersion Heater / Electric Element Fault | View Details |
| A11 |
Display shows A11; water heater indicates high pressure or safety valve activation.
|
Overpressure in Cylinder / Safety Valve Activation | View Details |
| A12 |
Display shows A12; water heater indicates low pressure in heating circuit (for indirect systems).
|
Low System Pressure in Primary Heating Circuit | View Details |
| A13 |
Display shows A13; water heater indicates sensor fault on solar coil or additional heat source coil.
|
Auxiliary Coil Temperature Sensor Fault | View Details |
| A14 |
Display shows A14; water heater indicates legionella protection fault or failed high-temperature cycle.
|
Legionella Protection Cycle Failure | View Details |
| A15 |
Display shows A15; water heater indicates internal control fault or EEPROM error.
|
Control Board Internal Error | View Details |
| A16 |
Display shows A16; water heater indicates sensor short-circuit or overrange on one of the NTC inputs.
|
Generic NTC Sensor Short-Circuit | View Details |
| A17 |
Display shows A17; water heater indicates sensor open-circuit or underrange on one of the NTC inputs.
|
Generic NTC Sensor Open-Circuit | View Details |
| A18 |
Display shows A18; water heater indicates flow switch fault or no flow detected when pump is running.
|
Flow Switch / Flow Sensor Fault | View Details |
| A19 |
Display shows A19; water heater indicates sensor fault on cold water inlet or mixing valve sensor (if equipped).
|
Cold Inlet / Mixing Valve Sensor Fault | View Details |
| A20 |
Display shows A20; water heater indicates maximum runtime exceeded for heater or pump.
|
Maximum Runtime / Overrun Protection | View Details |
| – |
Hot water has a metallic or rusty color when first drawn from taps connected to the Nibe water heater.
|
Internal Corrosion / Anode Depletion | View Details |
| – |
Hot water has a rotten egg or sulfur smell when using taps supplied by the Nibe water heater.
|
Bacterial Growth / Sulfide Reaction in Cylinder | View Details |
| – |
Hot water runs out very quickly; initial water is hot but becomes cold after a short time.
|
Reduced Effective Storage Volume / Stratification Problem | View Details |
| – |
Water heater causes noticeable vibration in nearby pipework and structure during operation.
|
Hydraulic Vibration / Water Hammer | View Details |
| – |
Water heater connected to a Nibe heat pump does not receive heat; coil connections remain cold while heat pump runs.
|
No Heat Transfer from External Heat Source | View Details |
| – |
Water heater cycles on and off rapidly, with short heating periods and frequent restarts.
|
Short Cycling / Control Instability | View Details |
| – |
Water heater display is on but buttons or touch controls do not respond.
|
User Interface / Keypad Failure | View Details |
| – |
Water heater does not start after a power outage; display is blank or unresponsive.
|
No Power / Control Panel Failure | View Details |
| – |
Water heater emits a humming or buzzing noise from the circulation pump area.
|
Circulation Pump Noise / Partial Seizure | View Details |
| – |
Water heater frequently drips water from the safety valve discharge pipe.
|
Frequent Safety Valve Discharge | View Details |
| – |
Water heater is leaking from the bottom or around connections; puddles form under the Nibe cylinder.
|
Water Leak from Cylinder or Fittings | View Details |
| – |
Water heater makes loud banging or knocking noises when heating.
|
Kettling / Boiling Noise Due to Scale or Local Overheating | View Details |
| – |
Water heater produces no hot water at all; taps run cold despite power being available.
|
Complete Loss of Heating Function | View Details |
| – |
Water heater provides only lukewarm water; temperature at taps is lower than setpoint and drops quickly.
|
Insufficient Hot Water Temperature / Capacity | View Details |
| – |
Water heater trips the electrical breaker or RCD when heating starts.
|
Electrical Short or Earth Leakage from Heater | View Details |
| – |
Water heater’s external casing is unusually hot to the touch and heat loss seems high.
|
Insulation Degradation / Heat Loss | View Details |
| – |
Water heater’s hot water temperature fluctuates significantly during a single shower.
|
Unstable Outlet Temperature / Mixing Valve or Control Issue | View Details |
No matching codes found
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