BoilerFaultCodesYour boiler's internal computer has lost its identity settings and doesn't know which specific model it is supposed to be.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: DSN appliance variant setting
What causes this fault?
This fault occurs when the boiler's main control board loses its memory of which specific model it is installed in. The most common reason is that a new control board has been fitted but not yet programmed with the correct identity code, or an electrical surge has corrupted the board's internal settings.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
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A boiler cover plan would cover faults like D.93 — no call-out fees, no surprises.
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Could it be time for a new boiler?
If repair costs are adding up, a new energy-efficient boiler could be the smarter long-term choice.
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