High Lockout
14 on Intergas Compact HRE OV

Your boiler has detected a problem with its primary temperature sensor and has shut down as a safety precaution to prevent overheating.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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

Sensor fault S1

What causes this fault?

This fault occurs when the boiler's main flow sensor sends an incorrect or interrupted signal to the control board, suggesting the sensor has either failed or become disconnected. The most common reason is general wear and tear of the internal thermistor or moisture damage affecting the electrical contacts within the sensor wiring.

Engineer required

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

Find a Gas Safe engineer
Search the official register →

Related fault codes

20View →24View →

Related guides you might find useful

Boiler keeps cutting out

Lockout fault with a reset-needed pattern.

Read →

When to replace your boiler

7 signs repair isn't worth it anymore.

Read →

Is boiler cover worth it?

Break-even maths on monthly cover.

Read →