How much does it cost to fix Potterton error code Error 20?

Typical repair cost for the Potterton Error 20 fault is £150-250 including labour.

Error 20 High

Potterton Error 20 Fault Code

Q: What does the Potterton Error 20 fault code mean?

Your boiler has lost the ability to accurately measure the temperature of the water, so it has safely shut itself down to prevent overheating.

Also written as ERROR20 — same fault.

The Potterton Error 20 fault code means: your boiler has lost the ability to accurately measure the temperature of the water, so it has safely shut itself down to prevent overheating.. It appears on 2 Potterton models in our database.

Technical description: Temperature sensors faulty (DHW and CH sensors)

Typical repair cost £150-250 (including labour)

Engineer required

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

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Potterton models that show the Error 20 fault code

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

Source

Potterton Error 20 fault code information on this page is sourced and cross-checked against the official Potterton service / installation manuals for each affected model.

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