High Lockout
432 on Ideal Ideal Classic SE15P FF

Your boiler has detected a fault with one of its internal temperature sensors, which is preventing the system from heating up safely.

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

NTC2 short circuit

What causes this fault?

This fault occurs when the boiler's internal temperature sensor develops an electrical short, causing it to send an incorrect signal to the main control board. The most common reason is that the sensor has suffered internal failure due to age, or moisture has compromised the electrical connections between the sensor and the wiring harness.

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.

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