Remeha d9 Fault Code

Also written as D9 — same fault.

The Remeha d9 fault code means: your boiler has detected that the water inside is heating up too quickly or is struggling to circulate, so it has safely shut itself down to prevent internal damage.. It appears on 1 Remeha model in our database.

Technical description: Shut down; maximum temperature rise is exceeded or the dT between the supply and return temperature ≥ 45°C or a rate of rise in the flow temperature > 1°C/sec