What does the Baxi 600 Series E900 fault code mean?
The E900 fault code on the Baxi 600 Series indicates that there is low water pressure in the domestic hot water (DHW) system. This can lead to inadequate hot water supply and may require immediate attention to restore proper function.
Common Causes
- Low System Pressure: The pressure in the boiler may have dropped below the minimum required level, often due to leaks or insufficient water supply.
- Faulty Pressure Relief Valve: A malfunctioning pressure relief valve can cause water to escape, leading to low pressure in the system.
Can I fix it myself? (DIY)
You can attempt to fix the low water pressure by checking the pressure gauge on the boiler and re-pressurising the system if necessary. If the pressure is below 1 bar, use the filling loop to add water until it reaches the recommended level. However, if you suspect a leak or a more serious issue, it is advisable to call a Gas Safe Engineer.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for addressing the E900 fault could range from £100 to £250, depending on whether it involves simply re-pressurising the system or replacing a faulty component like the pressure relief valve.