Heatline
Vizo 24
Combi Boiler
24kW
2014-2018
ErP A
40 fault codes
<p>The Vizo 24 is a combi boiler from Heatline, available at 24kW output. Produced 2014-2018.</p>
Vizo 24 Fault Codes 40
Code
Description
Severity
Type
F00
Flow Temperature Sensor Fault
The heating flow temperature sensor (F00) or return sensor (F01) has a wiring or sensor fault.
Medium
Engineer
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F20
Overheat Fault
The boiler has overheated and the safety limiter has activated. Caused by poor circulation, low water…
High
Engineer
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F22
Low Water Pressure
System water pressure has dropped below the safe minimum for the boiler to operate.
Low
DIY
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F23
Flow/Return Temperature Difference Too High
The temperature difference between flow and return is excessive, indicating circulation problems.
Medium
Engineer
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F24
Water Circulation Fault
The boiler has detected insufficient water circulation. Isolation valves may be closed or the pump may…
Medium
Engineer
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F26
Gas Valve Motor Fault
The gas valve motor has a fault, or the condensate pump is not operating correctly.
High
Engineer
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F27
Flame Detection Fault
The flame detection electrode has a fault. The boiler may ignite but cannot confirm the flame…
High
Engineer
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F28
Ignition Failure
The most common Heatline fault code. The boiler has failed to ignite. Very commonly caused by…
Medium
DIY
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F29
Flame Loss During Operation
The boiler ignited but then lost its flame during operation. Often caused by gas supply issues…
Medium
DIY
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F32
Incorrect Air Pressure / Flue Fault
The air pressure switch is not confirming correct airflow. May indicate a blocked flue, fan fault,…
High
Engineer
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F49
eBUS Communication Fault
There is a communication fault on the eBUS — the communication bus between the boiler and…
Medium
Engineer
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F72
Flow/Return Sensor Temperature Drift
A permanent temperature difference has been detected between the flow and return sensors, indicating a sensor…
Medium
Engineer
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F73
Heating Circuit Pressure Sensor Fault
The heating circuit water pressure sensor has a fault.
Medium
Engineer
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F76
Thermal Fuse Fault
The thermal fuse on the heat exchanger has blown due to extreme overheating. The heat exchanger…
High
Engineer
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F83
No Water Detected / Dry Fire
The boiler has fired but no temperature rise was detected, indicating the system has no water…
High
Engineer
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