H21-048 High

Ideal H21-048 Fault Code

Also written as H21048 — same fault.

The Ideal H21-048 fault code means: your boiler's fan unit is failing to spin or communicate correctly, which forces the boiler to shut down to prevent unsafe combustion.. It appears on 6 Ideal models in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: Fan (mod. miniHEC24)
Typical repair cost £180-350 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Ideal models that show the H21-048 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Ideal H21-048 fault code information on this page is sourced and cross-checked against the official Ideal service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026