black iron

andrew_3

I am installing a Munchkin 199 with an indirect and circulator controlled zones. My plumber says he prefers black iron for the near boiler piping. I have black iron nipples connecting circulator to manifold but had intended 1 inch Cu on all manifold cicuits and 1.25 inch Cu on the near boiler with the circulator on the in side. All loops are O2 pex.
Should I insist on Cu throughout?

andrew_3

munchkin and black iron

Anyone any answers on this question I posted yesterday? Is black iron a problem with the munchkin and O2 pex

Mark Eatherton1

Iron and 02 PEX

I presume you are not using an oxygen barrier PEX.

If not, there are basically 3 ways to protect ferrous components. One is to use all non ferrous components, and obviously, your plumber has poopooed that idea.

The other way is to maintan a pH in the system fluids of around 8.5 This water will remain relatively neutral to the ferrous components.

The third way is to use a stainless steel or other non ferrous heat exchanger to isolate the non barrier components from the ferrous components. This gets even more expensive becuase now you'll need twice as many pumps and air separators, half of which need to be non ferrous.

So, how much money are you going to save using non oxygen barrier tubing? Is it really worth the hassle? Not for my money. Every system we do is done with barrier tubing. I can sleep at night, knowing that if the home sells and the new owner neglects the system that I won't be getting the nightmare call about dissolved heating components.

Remember, "Rust never sleeps".

ME