Doram I don’t have DI water. I have Ashbeck (for now). 2. My boiler is stainless steel, so I think I have no problem. Please correct me if I’m wrong.
The chlorides are not good for stainless steel of any grade, especially if scale is involved. How long it takes for it to be a problem is anyone’s guess. How long you’ll get before Ashbeck starts to form scale is another guess - you’ll be feeding the boiler with the remineralised water so I think it’ll happen quite quickly. Probably not worth the effort.
MediumRoastSteam The Rancilio Silvia Pro has two independent circuits, with independent pumps. The DIY enthusiasts could make a modification to have a partition in the tank and have two different grades of water.
Makes perfect sense with two water tanks. I don’t know why more machines don’t have this functionality, I guess because it’s not something people want so it’s not something they bother with.
Doram The question is if there is any benefit in doing the above in term of scaling risk, as the remineralised water will still be circulated in the pipes, valves and group?
You’ll either get scale or you won’t. You can determine whether the water will scale or not in your boiler and in your HX quite easily, using the hardness, alkalinity and temperature. Does the HX temp equal the boiler temp sometimes? If it does there’s no point…if not then you can figure it out based on whatever temp it does reach.