BoilerFaultCodesTechnical description
Flow / Return - sensor check is running, demand (DHW or heating) is blocked
What causes this fault?
This occurs when the boiler detects a discrepancy between the readings of its two internal temperature sensors, prompting it to briefly pause for a self-test. The most common reason is that one of the sensors is beginning to fail or is giving an inaccurate reading compared to the other. If the sensors do not align after this check, the boiler may eventually shut down to prevent overheating.
DIY fix possible
Wait for 5 to 10 minutes as this is often a self-correcting diagnostic checkEnsure your radiator valves are open to allow water to circulateCheck that your system pressure is between 1.0 and 1.5 bar on the gauge
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