Low
203 0 on Worcester Bosch Greenstar 30i

Your boiler is working perfectly fine and is simply waiting for a signal from your thermostat to start heating.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

What the manual says

Manufacturer manual

Boiler in standby – no heat energy demand

Shared across the range
This code is shared by the boilers in this range, which use the same control board. It may not be printed in this exact variant’s manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

DIY fix possible

Check if your room thermostat is turned up higher than the current room temperature.Ensure your heating programmer or timer is set to an 'ON' period.Replace the batteries in your wireless wall thermostat if the screen is blank.

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