Copper tube thickness for near boiler

rsilvers

I see that black steel 1-1/2 is about $8 a foot. Copper L is $10. Copper K is $15. 

Which copper would you use to connect the boiler to a hydro separator and then to make manifolds to feed the zone pumps? L or K?

MikeL_2

  I use type m cu. Are you sure you need 1.5" piping?

rsilvers

If I used 1.25 inch I would have about 4.75 fps of water velocity and extra head if I used a 20 degree delta. It would work but the boiler has 1.5 inch threads. 

hot_rod

1-1/4 type M would be workable,a 25 delta would be an option also to lower the flow rate a bit. Nothing sacred about a 20 delta😗

rsilvers

I know. 4.6 fps if I do a 20 degree drop. 

It’s ok, but at the edge. I may end up doing a 25 degree drop but won’t know until it is done and pump settings are being programmed. It’s hard to calculate as it will be outdoor reset. 

hot_rod

The are some engineers that will push 5 fps velocity in hydronic systems. Above 5 you start to get some hissing noise. Like when an outside faucet is running full flow.

bburd

There is certainly no reason to use type K copper; that is heavy wall, normally used for underground service.

rsilvers

Yeah. I learned that is the case. I bought L.