BoilerFaultCodes AL10
Ignition failure/not flame sensed, condense sensor activated
Vokera Unica 28 HE Fault codes & diagnostics
15 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Combi Natural Gas 2006-present
GC Number 47-094-83
Download the Vokera Unica 28 HE manual
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Severity at a glance
Each cell = one fault code. Hover to identify. 15 Unrated
Fault codes
All 15 documented codes
Tap any card for details
AL20
Limit thermostat fault
AL21
External device fault (UHT/CPA)
AL26
Return temperature too high
AL28
Temperature differential inverted (return sensor temperature higher than thermistors flowsensor temperature)
AL34
Fan tacho signal fault
AL40
Insufficient system water pressure
AL41
Insufficient system water pressure
AL52
Internal fault
AL55
Jumper tag fault
AL60
DHW thermistor fault
AL71
Primary (flow) thermistor fault
AL73
Return thermistor fault
AL74
Variation on temperature of primary and/or return too high
AL79
Flow temperature too high, or
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