1 to 9, h, l, b Low

Remeha 1 to 9, h, l, b Fault Code

Also written as 1TO9HLB — same fault.

The Remeha 1 to 9, h, l, b fault code means: your boiler is displaying standard status codes to show it is working normally or warming up, rather than indicating a fault.. It appears on 1 Remeha model 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: operating mode codes

What causes the Remeha 1 to 9, h, l, b fault?

These codes appear because the boiler is communicating its current stage of operation, such as starting the fan or heating the water to the required temperature. They are triggered by normal requests for heating or hot water and do not indicate that anything has broken. Think of them as the boiler providing a live progress report on its internal sequence.

DIY fix possible

Check that your thermostat is set to the desired temperatureEnsure the gas and water supply valves are openMonitor the display to see if the code changes as the boiler completes its cycle

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Remeha models that show the 1 to 9, h, l, b fault code

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

Source

Remeha 1 to 9, h, l, b fault code information on this page is sourced and cross-checked against the official Remeha service / installation manuals for each affected model.

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