BoilerFaultCodesWhat the manual says
Manufacturer manualfan pre-run
From this model's manual
Verified against the Glow Worm/Glow Worm Ultracom2 12sxi installation & service manual, page 55.
What causes this fault?
This status code occurs when the boiler's internal computer begins the start-up sequence and tells the fan to spin up. It is checking that the fan can reach the correct speed to safely clear out any leftover gases before the burner ignites. The most common reason for this appearing is simply that the boiler is responding to a demand for heating or hot water.
DIY fix possible
This fault may be fixable without an engineer. Check your manual first.
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Related fault codes
All 75 fault codes on the Ultracom 2 SXI
Seeing a different code? Every code this model can display, in one place.