What does the Ideal 4 / A fault code mean?

Your boiler has detected that the internal water temperature is dangerously hot and has shut itself down to prevent damage or overheating.

How much does it cost to fix Ideal error code 4 / A?

Typical repair cost for the Ideal 4 / A fault is £150-250 including labour.

Temperature supply sensor too high (> 101 °C).

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

Each noise points to a different fault.

Lockout fault with a reset-needed pattern.

Sludge build-up — needs flushing, not bleeding.