BoilerFaultCodesYour boiler is temporarily pausing because it has detected a suspicious temperature difference and is double-checking that its heat sensors are working correctly before it continues.
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: Flow / Return - sensor check is running, demand (DHW or heating) is blocked
What causes this fault?
This fault occurs when the boiler's internal computer notices the temperatures on the two main pipes don't match up as expected. To prevent overheating, the system pauses briefly to test if the sensors are providing accurate data or if they are beginning to fail. The most common reason is one of the sensors becoming slightly out of calibration, causing a 'clash' in the readings.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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