BoilerFaultCodesYour boiler is struggling to adjust the heating temperature correctly in response to changes in the weather outside.
This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.
Technical description: Fast (low values) or slow (high values) matching of flow temperature subject to set value if the outside temperature changes
What causes this fault?
This fault occurs when the boiler's control system loses accurate data from the external sensor that tracks the weather. It is usually caused by a loose electrical connection, a damaged cable, or the sensor itself failing, which prevents the boiler from knowing how hot it needs to run to keep your home comfortable.
This issue is often first noticed in autumn or winter when the boiler needs to react more frequently to dropping outdoor temperatures.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
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A boiler cover plan would cover faults like 90:0 to 90:199 — no call-out fees, no surprises.
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