Heatrae Sadia unvented cylinder with electronic controls shows E10 and heating is disabled.

Safety first: Isolate electrical power and relieve system pressure carefully if opening any water connections. Hot pressurised water is dangerous.

Steps to address E10:

• 1. Check system pressure: If a pressure gauge is fitted, confirm that the system is within the specified cold fill pressure (typically around 3 bar for many unvented systems). Over- or under-pressure can trigger faults.
• 2. Inspect expansion and safety devices: Ensure the expansion vessel is correctly charged and that the pressure reducing valve is not blocked. A failed valve can cause abnormal pressure readings.
• 3. Locate pressure sensor: Identify the pressure transducer on the cylinder manifold or hydraulic block. Check for kinks or blockages in any sensing tube.
• 4. Electrical checks: With power off, inspect the sensor wiring and connector. Reseat the connector on the PCB.
• 5. Replace sensor if necessary: If the sensor is physically damaged or tests out of range, replace it with the correct Heatrae Sadia pressure sensor. Re-pressurise and test.
• 6. Professional help: Pressure-related faults on unvented cylinders should generally be handled by a G3-qualified engineer due to safety regulations.