BoilerFaultCodesYour boiler has lost connection with its outdoor thermometer, meaning it might struggle to adjust its temperature correctly for the weather.
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: The diagnostics will indicate the nature of the fault to assist a speedy and effective repair
What causes this fault?
This fault occurs when the communication link between your boiler and the external sensor is broken or sending illogical data. The most common reasons are moisture getting into the sensor casing, corroded electrical connections, or the thin wiring being accidentally damaged by garden maintenance or pests.
This fault is more common following periods of heavy rain or snow, which can cause moisture to penetrate the sensor housing and short-circuit the sensitive electronics.
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.
Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like Outside sensor (if fitted) — no call-out fees, no surprises.
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Ideal Concord CXA 40-120 is discontinued — time for a new one?
Parts for discontinued models can be hard to find and expensive. A new A-rated boiler could save you money on both repairs and energy bills.
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