S.36 High

Heatline S.36 Fault Code

Also written as S36 — same fault.

The Heatline S.36 fault code means: your boiler has detected that water is not circulating properly through the heating system, which is preventing it from distributing warmth to your radiators.. It appears on 8 Heatline 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: Heating Blockage
Typical repair cost £150-300 (including labour)

Engineer required

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

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Heatline models that show the S.36 fault code

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

Source

Heatline S.36 fault code information on this page is sourced and cross-checked against the official Heatline service / installation manuals for each affected model.

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