Originally Posted by Bondo
Ayuh,... You'll have to pick,+ choose where to make the transitions..
You can't weld something up, you need to transition at some joint somewhere...
Cutting,+ rethreading would be a nightmare...
So, I have two choices- at the radiator or at the elbow, possibly a mix of both (upstairs rads might be a bear). I assume that there are pretty standard PEX fittings that reduce 2" iron to an appropriate PEX diameter? Then run the PEX to a in/out trunk and back to the boiler.
The flow diagram that I have in my head is something like:
Main --> valve --> Boiler --> manifold a/b zone --> Circulation pump (a) --> Hot PEX Trunk --> Hot PEX Stem --> Hot Radiator --> Cold Rad --> Return stem --> return trunk --> expansion tank --> check valve --> boiler.
Am I missing any pieces? Drain valve at least and I'm not sure how the main to boiler water lever is monitored/controlled.
How do you calculate heat loss by volume/distance in a trunk and stem given material and insulation (PEX with low dense foam)?
Do I need an expansion tank for each zone or can both zones come into the same tank?