What does the Johnson Starley E04 fault code mean?

Your boiler has stopped working because the water pressure is too low for it to run safely.

How much does it cost to fix Johnson Starley error code E04?

Typical repair cost for the Johnson Starley E04 fault is £0-120 including labour.

Locate the external filling loop, which is usually a silver flexible hose with two small valves.

Insufficient water pressure in the system

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

Six most common causes of dropping pressure.

Step-by-step using the filling loop.

7 signs repair isn't worth it anymore.