203 0 Low

Worcester Bosch 203 0 Fault Code

Also written as 2030 — same fault.

The Worcester Bosch 203 0 fault code means: your boiler is working correctly but currently has no request from your thermostat or taps to provide heating or hot water.. It appears on 10 Worcester Bosch models in our database.

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.

Technical description: Boiler in standby – no heat energy demand

What causes the Worcester Bosch 203 0 fault?

This code is simply a status message indicating your boiler is waiting for a command to start. It occurs when your home has reached the desired temperature on your thermostat and no hot water taps are currently running. The boiler remains powered on and ready to react the moment it detects a drop in room temperature or a request for hot water.

This code is more visible during the summer months when the heating is switched off, as the boiler spends the vast majority of its time in this standby state.

DIY fix possible

Check that your room thermostat is turned up higher than the current room temperatureEnsure your heating programmer or timer is set to 'On'Check if the batteries in your wireless thermostat need replacing

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Worcester Bosch models that show the 203 0 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Worcester Bosch 203 0 fault code information on this page is sourced and cross-checked against the official Worcester Bosch service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026