Hi. Away from base and unable to check basic stuff in textbooks... and not something I come across very often.
Wondered if you can help remind me if I'm right in my recollection?
Have been looking at my father's boiler. It is a thermal store combi (very common in Italy) installed about 20 years ago (a right lash-up of a job, to be frank). The hot water supply from the combi feeds via copper tube to the (older) LCS 'iron' hot water pipework in the flat, installed in the early 1970s.
So we have mains supply in (galvanised?) iron --> copper --> boiler (stainless, I think) --> copper --> (galvanised?) iron. I have not noticed a sacrificial anode.
My concern is that, whether the iron tube is galv or not, the water really shouldn't be running through copper (and presumably stainless in the boiler itself) before it. There is a much older boiler plumbed entirely in iron also feeding the same flat (judicious use of isolation valves gives you a choice of which boiler supplies the hot water) and that fact that this older boiler has mostly been used, with the 'new' boiler being used rarely, may have prevented any evidence of damage but I'm concerned that the water coming through the copper will damage the iron pipework - which is all buried in the walls and floors!
Given that the there is a polyphosphate dispensor (very common in Italy) on the cold supply to the boiler, I was wondering whether polyphosphate acts as a corrosion inhibitor?
Regulations seem to differ over here - but the science must surely be the same.
Am I right in remembering that water should flow from most reactive metal to least reactive metal, and can anyone suggest whether this installation may be okay somehow (or should I get rid of the copper)?
Thanks for any assistance.
Wondered if you can help remind me if I'm right in my recollection?
Have been looking at my father's boiler. It is a thermal store combi (very common in Italy) installed about 20 years ago (a right lash-up of a job, to be frank). The hot water supply from the combi feeds via copper tube to the (older) LCS 'iron' hot water pipework in the flat, installed in the early 1970s.
So we have mains supply in (galvanised?) iron --> copper --> boiler (stainless, I think) --> copper --> (galvanised?) iron. I have not noticed a sacrificial anode.
My concern is that, whether the iron tube is galv or not, the water really shouldn't be running through copper (and presumably stainless in the boiler itself) before it. There is a much older boiler plumbed entirely in iron also feeding the same flat (judicious use of isolation valves gives you a choice of which boiler supplies the hot water) and that fact that this older boiler has mostly been used, with the 'new' boiler being used rarely, may have prevented any evidence of damage but I'm concerned that the water coming through the copper will damage the iron pipework - which is all buried in the walls and floors!
Given that the there is a polyphosphate dispensor (very common in Italy) on the cold supply to the boiler, I was wondering whether polyphosphate acts as a corrosion inhibitor?
Regulations seem to differ over here - but the science must surely be the same.
Am I right in remembering that water should flow from most reactive metal to least reactive metal, and can anyone suggest whether this installation may be okay somehow (or should I get rid of the copper)?
Thanks for any assistance.
