Vokera boiler troubleshooting

Most boilers stop working due to external factors rather than due to faulty designs. A malfunction must be diagnosed and eliminated, and you can do that using the troubleshooting table below. It describes the most common causes of malfunctions, and there are solutions in the opposite column.

VOKERA Mynute VHE boiler troubleshooting

CODE CAUSE ALARM TYPE ACTION
AL10 Ignition failure/not flame sensed, condense sensor activated Final Reset, check appliance operation
AL20 Limit thermostat fault
AL21 External device fault (UHT/CPA) Reset, check appliance
AL26 Return temperature too high Reset, check pump, ensure there is sufficient flow sensor temperature), circulation around heating circuit/s
AL28 Temperature differential inverted (return sensor temperature higher than flowsensor temperature) Reset, check pump, ensure there is sufficient circulation around heating circuit/s thermistors
AL34 Fan tacho signal fault Reset check appliance operation, check fan
AL52 Internal fault Reset, check appliance operation
AL55 Jumper tag fault Check jumper tag configuration
AL60 Temporary
AL71 Primary (flow) thermistor fault Check primary thermistor, check wiring
AL73 Return thermistor fault Check return thermistor, check /wiring
AL74 No water circulation Final Reset, check appliance operation, check pump, ensure there is water and sufficient circulation around heating circuit/s
AL79 Flow temperature too high, or temperature differential between primary and return too high Reset, check appliance operation, check thermistors

VOKERA Option boiler troubleshooting

Fault Possible causes Remedy
Appliance fires then lockouts Incorrect gas pressure flue blocked or broken Check incoming pressure and/or burner pressures check flue assembly
Appliance wont fire for hot water Hot & cold pipes reversed flow regulator blocked insufficient flow rate Check external plumbing remove and clean increase flow rate
Appliance wont fire for heating External control or wiring fault or wiring Check external controls
Appliance fires for heating but no circulation around system Flow & return service valves closed air in appliance pump stuck Open service valves open dustcap on ‘aav’ open vent plug on pump and rotate shaft flush system
Debris in system
Appliance inactive no ‘led’s showing Electrical supply fault blown fuse Check supply to appliance for 240v between ‘l’ & ‘n’ check and replace

VOKERA Vision 25C boiler troubleshooting

ALARM CODE CAUSE ALARM TYPE ACTION
St AUTOSTOP Final Call engineer
_CL CALL FOR SERVICE Temporary then Final
A01 Ignition failure, flame not sensed, internal fault Final Reset, check appliance operation
A02 Limit thermostat fault
A03 Fan tacho signal fault Reset check appliance operation, check fan
A04 Insufficient system water pressure Check/refill system pressure, reset, check appliance operation
A06 DHW thermistor fault Temporary Check DHW thermistor
A07 Primary (flow) thermistor fault Temporary Check primary thermistor, check wiring
Primary (flow) thermistor over temperature Temporary then Final Reset, check appliance operation
Temperature differential Final Reset, check appliance operation, check thermistors
A08 Return thermistor fault Temporary Check return thermistor, check wiring
Return thermistor over temperature Temporary then Final Reset, check appliance operation
Temperature differential inverted Final Reset, check pump, ensure there is sufficient circulation around heating circuit/s
A09 Flue thermistor or flue thermistor counter fault Temporary Check flue thermistor counter at power on, check flue thermistor, check wiring
Flue thermistor over temperature Final Reset, check appliance operation
A77 Low temperature thermostat fault Temporary Check low temperature thermostat
Adj Calibration Na None
ACO Service operation
P Preheating function active
P blinking Preheating function running
Flame Flame ON
Hours Stand-by
OFF