BoilerFaultCodesWhat the manual says
Manufacturer manualProduct in waiting period / operating block function due to water deficiency (flow/return spread too large)
From this model's manual
Verified against the Glow Worm Energy7 Regular installation & service manual, page 40.
DIY fix possible
Check the system pressure gauge on the front of the boiler; ensure it is between 1.0 and 1.5 barIf the pressure is below 1.0 bar, use the filling loop to top up the system until it reaches the correct rangeCheck all radiators to ensure they are bled of any trapped airEnsure all radiator valves are fully open
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