What the manual says
Manufacturer manualInsufficient pressure in central heating system. Indicated by the bottom red light on the left hand side of the facia illuminating (bar symbol).
From this model's manual
Verified against the _duplicates/Ferroli/Ferroli Domina 102 installation & service manual.
Engineer required
This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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All 26 fault codes on the Domina 102
Seeing a different code? Every code this model can display, in one place.
4 (Flashing)4 (Permanent Light)5 (Flashing)5 (Permanent Light)454750E03Heating demand light ONLED 4LED 4 (Flashing light)LED 4 (Permanent light)LED 5LED 5 (Flashing light)LED 5 (Permanent light)LED1LED2LED4 (Permanent)LED5 (Permanent)LED5 bar (Flashing)Low water pressure light ONRed LED Out (Lockout)Red light (Egg timer symbol)Red lockout lightTap symbol light ON