What does the Ravenheat E21 fault code mean?

Your boiler has sensed that the water returning from your radiators is too hot, causing the system to shut down for protection.

How much does it cost to fix Ravenheat error code E21?

Typical repair cost for the Ravenheat E21 fault is £100-220 including labour.

Check that all radiator valves (TRVs) are fully open

Central heating (CH) return sensor overheating

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

Sludge build-up — needs flushing, not bleeding.

Each noise points to a different fault.

7 signs repair isn't worth it anymore.