Vokera Furnaces Error Codes

01

Furnace fails to ignite, display shows 01 shortly after a call for heat

Ignition Failure / No Flame Detected

02

Furnace locks out with 02, fan runs but burner does not light

Flame Loss During Operation

03

Display shows 03 and furnace will not start, fan may not run

Fan / Air Pressure Fault

04

Furnace shows 04 and shuts down, often after running for a short time

Overheat / High Limit Thermostat Trip

05

Code 05 displayed, furnace does not respond to thermostat demand

Flow Temperature Sensor Fault

06

Display shows 06, furnace may run erratically or not at all

Return Temperature Sensor Fault

07

Furnace shows 07 and will not fire, often after power-up

Flow Sensor / Thermistor Short Circuit

08

Code 08 appears, furnace may overheat or shut down unexpectedly

Return Sensor / Thermistor Short Circuit

09

Furnace displays 09 and will not start, often after a power surge

EEPROM / PCB Configuration Error

10

Code 10, furnace does not start, fan may run briefly then stop

Flue Gas Overheat / Flue Thermostat Trip

11

Display shows 11, furnace will not fire, fan may not start

Fan Speed / Tachometer Fault

12

Code 12, furnace cycles on and off rapidly or fails to modulate correctly

Flow Temperature Rise Too Fast

13

Furnace shows 13, burner shuts down, may coincide with high system temperature

Return Temperature Rise Too Fast

20

Code 20, furnace unresponsive to thermostat, no call for heat recognized

Room Thermostat / External Control Fault

21

Display shows 21, furnace may run at incorrect output or not respond to modulation

Communication Fault with External Controller

23

Code 23, furnace stops and may show abnormal temperature readings

Flow Sensor Out of Range / Calibration Error

24

Display shows 24, furnace may lock out or modulate incorrectly

Return Sensor Out of Range / Calibration Error

27

Code 27, furnace fails to ignite or shuts down shortly after ignition attempt

Gas Valve Control Fault

28

Furnace shows 28, ignition attempts may be noisy or irregular

Ignition Control / Spark Fault

29

Code 29, furnace may light but then shut down, sometimes with yellowish flame

Poor Combustion / Low Ionisation Current

31

Display shows 31, furnace may not start or may shut down unexpectedly

Low System Water Pressure (for hydronic furnace models)

32

Code 32, furnace locks out, pressure gauge may show high reading

High System Water Pressure

33

Furnace shows 33, intermittent operation, pressure reading fluctuates

System Pressure Sensor Fault

40

Code 40, furnace fan runs but burner does not light, may indicate air pressure issue

Air Pressure Switch Open When Should Be Closed

41

Display shows 41, furnace may attempt to start with fan off or at wrong time

Air Pressure Switch Closed When Should Be Open

50

Code 50, furnace unresponsive, display may be blank or frozen

General PCB / Power Supply Fault

Symptom

Furnace blower runs continuously even when there is no call for heat

Fan Stuck On / Control Fault

Symptom

Furnace causes vibration or rumbling transmitted through the house

Mechanical Vibration / Mounting Issue

Symptom

Furnace does not respond to thermostat changes, but display appears normal

Control / Thermostat Communication Issue

Symptom

Furnace emits a burning smell or plastic smell when running

Overheating Component or Foreign Material on Heat Exchanger

Symptom

Furnace emits a gas smell around the unit, especially at start-up

Gas Leak or Incomplete Ignition

Symptom

Furnace flue terminal shows signs of black soot or staining

Sooting / Poor Combustion

Symptom

Furnace frequently locks out and requires manual reset, with varying codes or no code

Intermittent Lockout / Unstable Operation

Symptom

Furnace frequently loses pressure and needs topping up

Chronic System Pressure Loss

Symptom

Furnace is completely dead, no lights or display, does not respond to thermostat

No Power to Furnace

Symptom

Furnace produces a whistling or high-pitched noise during operation

Combustion or Airflow Resonance

Symptom

Furnace runs but makes loud banging or booming noises at ignition

Delayed Ignition / Burner Light-Off Noise

Symptom

Furnace runs but produces no heat to the home (blower runs, but supply air is cool)

Burner Not Firing Under Call for Heat

Symptom

Furnace short cycles (starts and stops frequently) without reaching set temperature

Short Cycling / Overheat or Control Issue

Symptom

Furnace starts but shuts down after a few minutes, house never reaches set temperature

Overheat Trip or Poor Circulation

Symptom

Visible water dripping from the flue terminal outside

Condensate Discharge / Flue Condensation

Symptom

Water leaking from the bottom of the furnace cabinet

Internal Water Leak