Saunier Duval
Opalia C11E System
System Boiler
24kW
2008-2017
ErP A
35 fault codes
<p>The Opalia C11E System is a system boiler from Saunier Duval, available at 24kW output. Produced 2008-2017.</p>
Opalia C11E System Fault Codes 35
Code
Description
Severity
Type
F1
Ignition Failure / Lockout
The boiler has failed to ignite. The most common Saunier Duval fault code across all their…
Medium
DIY
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F10
CH Return Thermistor Fault
The central heating return temperature sensor has a fault.
Medium
Engineer
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F14
Flow Temperature Above 95°C
The flow temperature has exceeded 95°C — a serious overheat condition.
High
Engineer
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F16
False Flame After Burner Stop
The boiler has detected a flame signal for more than 5 seconds after the burner was…
High
Engineer
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F17
Low Mains Voltage
The mains power supply voltage has dropped below 170V — too low for safe operation.
Medium
Engineer
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F19
CH Thermistor Disconnected
The central heating temperature thermistor appears to have become unplugged or disconnected.
Medium
Engineer
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F2
Flame Supervision Fault
The flame signal is not being detected correctly.
High
Engineer
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F20
Software Incompatibility
The user interface or main board has incorrect or incompatible software.
Medium
Engineer
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F23
Water Circulation Fault
Insufficient water circulation detected — possible pump failure.
Medium
Engineer
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F25
Flow Temperature Rising Too Fast
The flow temperature is rising at an unsafe rate — possible pump failure or severe airlock.
High
Engineer
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F26
Maximum Delta Temperature
The temperature difference between flow and return is too great — water circulation fault or flow/return…
Medium
Engineer
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F28
Permanent Flow/Return Sensor Drift (Thema)
On Saunier Duval Thema boilers, F28 indicates a permanent temperature drift between the flow and return…
Medium
Engineer
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F29
Thermal Fuse Fault
The thermal fuse on the heat exchanger has activated — requires heat exchanger replacement.
High
Engineer
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F4
Flame Lost During Operation
The boiler ignited but then lost the flame during operation. On some Saunier Duval models, F4…
Medium
DIY
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F5
Overheat Fault
The overheat safety thermostat has operated on the boiler. Usually caused by poor circulation, low water…
High
Engineer
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F6
CH Flow Thermistor Fault
The central heating flow temperature sensor has a fault.
Medium
Engineer
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F7
DHW Thermistor Fault
The domestic hot water temperature sensor has a fault.
Medium
Engineer
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F8
Slow Temperature Rise
The temperature is not rising fast enough after ignition.
Medium
Engineer
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F9
Water Pressure Sensor Fault
The water pressure sensor has a faulty connection or has failed. Check wiring.
Medium
Engineer
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