BoilerFaultCodesTechnical description
Different temperature error
What causes this fault?
This fault occurs when the boiler detects a significant temperature difference between the flow and return pipes, meaning heat isn't leaving the unit fast enough. The most common reason is a lack of water circulation caused by a failing pump, a blockage in the internal pipework, or air trapped within the system.
This issue is more common in autumn when heating systems are first turned on after a long summer break, as pumps can seize during periods of inactivity.
Engineer required
This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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