High
1021 B on Worcester Bosch Junior 24i

Your boiler's hot water sensor is not reporting correctly, which means the system cannot safely heat your water to the right temperature.

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

Hot water temperature sensor is defective – the plug to the hot water temperature sensor may not be connected

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

Related guides you might find useful