How often does a tankless water heater need to be descaled?
Testo:
I have a Rinnai RL94 Tankless hot water heater. It’s not clear to me from the owner’s manual whether the unit needs to be descaled regularly, or whether it’s all right to wait for one of the corresponding “LC” warning codes to appear. I know this depends on the hardness of my local water supply. Is this something that I would be doing pre-emptively, or is it all right to just wait for the warning?