High Lockout
E38 on Remeha Avanta 18V

Your boiler has stopped working because its internal temperature sensor that monitors water returning to the unit has developed an electrical fault.

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

NTC return sensor short circuit

What causes this fault?

This fault occurs when the sensor responsible for measuring the temperature of the water returning to the boiler develops an electrical short circuit. The most common reason is that the internal components of the sensor have failed due to age or heat stress, though it can also be caused by water leaking onto the electrical connections.

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

E37View →

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 →