How much does it cost to fix Potterton error code Blocking?

Typical repair cost for the Potterton Blocking fault is £120-250 including labour.

Blocking High

Potterton Blocking Fault Code

Q: What does the Potterton Blocking fault code mean?

Your boiler has switched itself off because it has detected an issue with its internal safety sensors or the electrical supply, and it needs a professional to investigate the cause.

Also written as BLOCKING — same fault.

The Potterton Blocking fault code means: your boiler has switched itself off because it has detected an issue with its internal safety sensors or the electrical supply, and it needs a professional to investigate the cause.. It appears on 5 Potterton models in our database.

Technical description: Green LED: ON, Red LED: FLASHING 2 Per Sec. Causes: Mains Frequency incorrect or Air Switch Fault > 1 min. or Reset button held in to force a restart.

Typical repair cost £120-250 (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 Blocking fault code

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

Source

Potterton Blocking 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