Water heater scale

[noelex 77]

Water heater scale
I have a raritan 50l water heater that will heat water from 240v or a nanni 15hp engine (12v generator). The heat exchanger of the nanni was replaced last year and I disconnected the water heater as the coolant in the old heatexchanger (& so also in the coolant pipes of the waterheater ) was brown. I didn't want this going through the new heatexchanger.
I decided today to flush out the water heater. To my dismay I find even after pumping 100 l through the waterheater pipes (both ways) & poking a metal spiral drain unblocker I am still getting the occasional brown blobs coming out. The brown blobs are typically 2mm square & look like rusty metal but are non metallic & feel like mud between the fingers.
Is this sort of scale, rust, or whatever it is, normal in the pipes, which I presume are copper, of a waterheater ? Should I replace the waterheater?should I try some car radiator cleaner or other chemical cleaner.
Any advice greatly appreciated
john

[Pblais]

Should I replace the waterheater?should I try some car radiator cleaner or other chemical cleaner.

Would you want to drink the water after you did it? You can do all the things you can do to a car radiator but then I wouldn't drink that water either.

If the rust is inside the water heater then the inside of the heater has rusted. Not all the rust is loose so more losens up over time. You could toss it out or wait for it to start leaking. A little bit of rust won't hurt you but hash chemicals could and it won't stop rusting.

[noelex 77]

Thanks for the reply. The water out of the tap is not "rusty" only the water in the heat exchanger part of the water heater. My understanding is that this is a copper tube (which shouldn't rust !!)inside the water that is consumed therefore the water could be treated with chemicals, it will get inside my engine, but not in the drinking water. I probably didn’t explain it well or maybe I misunderstand how the heater works ?