While you wait for answers, we may have found some information which could help you.
Click here for Boiler Thermostat OverheatingRemeha boiler backfiring?
pressure gauge fault?
Remeha Avanta Plus 28c no hot water but still have heating?
How can I fix my programmer RWB2 ?
I have a Remeha boiler - there is no error message but the rads dont work?
How can I fix my Remeha Avanta Plus boiler?