Vokera Boilers Error Codes

01

Boiler will not ignite, display shows fault code 01, no heating or hot water

Ignition Failure / Flame Not Detected

02

Boiler locks out with code 02, fan runs but no ignition, or ignition stops quickly

Flame Detection Failure / Flame Signal Lost

03

Boiler shows 03 and shuts down, fan may not start, no ignition sequence

Fan / Air Pressure Switch Fault

04

Boiler displays 04 and locks out, no heating or hot water

Ignition Lockout / Repeated Failed Starts

05

Boiler shows 05, will not fire, may attempt ignition then shut down

Overheat Thermostat Tripped

06

Boiler displays 06, temperature rises rapidly then locks out

Flow Temperature Sensor Fault / Overheat Detection

07

Boiler shows 07, may run briefly then shut down, temperature readings erratic

Return Temperature Sensor Fault

08

Boiler displays 08, no heating or hot water, may indicate flue/air fault

Air Pressure Switch / Flue System Fault

09

Boiler shows 09, fan runs continuously or not at all, no ignition

Fan Speed / Fan Feedback Fault

10

Boiler displays 10, no heating or hot water, may indicate flue/ventilation issue

Flue Gas Safety / Combustion Fault

11

Boiler shows 11, will not start, may indicate low water pressure or circulation fault

Low System Pressure / Water Circulation Fault

12

Boiler displays 12, heating demand not recognised or boiler cycles rapidly

Flow Switch / Flow Sensor Fault (DHW or CH depending on model)

13

Boiler shows 13, temperature readings unstable, boiler may short-cycle

Domestic Hot Water NTC Sensor Fault

20

Boiler displays 20, no response to thermostat, heating will not start

External Control / Room Thermostat Circuit Fault

23

Boiler shows 23, may indicate pump or circulation fault, overheating on flow

Pump Fault / Insufficient Circulation

24

Boiler displays 24, pressure gauge may be high, water discharged from PRV

High System Pressure / Expansion Vessel Fault

25

Boiler shows 25, no heating, may indicate sensor or PCB fault

General Temperature Sensor / PCB Fault

27

Boiler displays 27, intermittent lockouts, may relate to ionisation/flame signal

Flame Signal Instability

40

Boiler shows 40, no heating or hot water, may indicate lockout due to repeated faults

General Lockout / Multiple Fault Condition

A01

Vokera boiler (e.g. Compact, Easi-Heat, Vision) shows A01, no flame detected

Ignition Failure (Modern Alpha Code)

A02

Boiler shows A02, overheat condition, boiler very hot then shuts down

Primary Circuit Overheat

A03

Boiler displays A03, fan/flue related fault, no ignition

Flue Fan / Air Pressure Fault (Alpha Code)

A04

Boiler shows A04, low water pressure, no heating

Low System Pressure (Alpha Code)

A06

Boiler displays A06, NTC sensor fault indicated, boiler may not fire

Flow or Return NTC Sensor Error (Alpha Code)

A07

Boiler shows A07, DHW temperature sensor fault, unstable hot water temperature

DHW NTC Sensor Error (Alpha Code)

A08

Boiler displays A08, pump or circulation related fault, may overheat quickly

Pump / Circulation Fault (Alpha Code)

A09

Boiler shows A09, flue gas over-temperature or flue sensor fault (on models fitted)

Flue Gas Temperature Fault

Symptom

Boiler display is on but does not respond to controls or buttons

User Interface / Control Panel Fault

Symptom

Boiler frequently loses pressure and needs topping up every few days

Chronic Pressure Loss

Symptom

Boiler leaking water from underneath the casing or pipe connections

Internal Water Leak

Symptom

Boiler locks out more often during very cold weather, external pipework affected

Frozen Condensate Pipe

Symptom

Boiler makes loud banging or kettling noises during operation, especially on heating

Kettling / Localised Boiling in Heat Exchanger

Symptom

Boiler makes loud humming, vibrating, or rattling noises during operation

Mechanical Vibration / Resonance

Symptom

Boiler or flue emits unusual smells (burning, metallic, or exhaust-like odour)

Combustion / Overheating Smell

Symptom

Boiler provides hot water but central heating does not come on, even though thermostat is calling

No Central Heating Demand / Diverter Valve Stuck

Symptom

Boiler randomly turns off and on, or cuts out before reaching set temperature

Short Cycling / Intermittent Operation

Symptom

Boiler runs for central heating but does not provide any hot water at the taps

No Domestic Hot Water on Combi Boiler

Symptom

Boiler will not start at all, no lights or display

No Power / Dead Boiler

Symptom

Condensate water dripping from the bottom of the boiler casing or flue joints

Condensate Drain / Trap Issue

Symptom

Hot water temperature fluctuates between hot and cold when using a tap or shower

Inconsistent Domestic Hot Water Temperature

Symptom

Radiators only get warm at the bottom or some radiators stay cold while boiler runs

Poor Heating Circulation / Sludge Build-up