Converting 1 inch monoflow copper to Pex

[Al S]

I have a one inch monoflo trunk of copper that makes it way around the key areas of the basement that serves convectors via 1/2 pipe and the monoflo tees are on the supply side not the return side. The trunk is about 8 inches below the joists in the basement and I wanted to raise that trunk up to at least the faces of the joists. Since I am using PEX B (crimp connections), do I need to upsize to 1 1/4 PEX even though it feeds 1/2 inch tees. I guess the 1/2 inch pipe will be slightly smaller than the 1/2 inch copper. The flow will be obviously affected and my circulator pump is set to medium speed (default) for the copper circuit.

The questions then is: Has anyone made the switch? What were the lessons learned?

Thanks to all in advance
Al

 

[Sylvan]

I have a one inch monoflo trunk of copper that makes it way around the key areas of the basement that serves convectors via 1/2 pipe and the monoflo tees are on the supply side not the return side. The trunk is about 8 inches below the joists in the basement and I wanted to raise that trunk up to at least the faces of the joists. Since I am using PEX B (crimp connections), do I need to upsize to 1 1/4 PEX even though it feeds 1/2 inch tees. I guess the 1/2 inch pipe will be slightly smaller than the 1/2 inch copper. The flow will be obviously affected and my circulator pump is set to medium speed (default) for the copper circuit.

The questions then is: Has anyone made the switch? What were the lessons learned?

Thanks to all in advance
Al

I have converted monoflow to two pipe systems using schedule 40 steel.
Less heat loss than copper, and velocity is not as critical

Also, I converted a one-pipe steam system to a two-pipe hydronic system using the same boiler

 

[Sponsor]

 

[Fitter30]

I have a one inch monoflo trunk of copper that makes it way around the key areas of the basement that serves convectors via 1/2 pipe and the monoflo tees are on the supply side not the return side. The trunk is about 8 inches below the joists in the basement and I wanted to raise that trunk up to at least the faces of the joists. Since I am using PEX B (crimp connections), do I need to upsize to 1 1/4 PEX even though it feeds 1/2 inch tees. I guess the 1/2 inch pipe will be slightly smaller than the 1/2 inch copper. The flow will be obviously affected and my circulator pump is set to medium speed (default) for the copper circuit.

The questions then is: Has anyone made the switch? What were the lessons learned?

Thanks to all in advance
Al

Why not cut the 1/2" off with a stub just raise all the 1" copper up. Run pex off the stubs with adaptors to pex. Pex has to have a oxygen barrier made for heating systems.

 

[Al S]

Thanks. That's a good hybrid solution. I have to be mindful of the areas where a potential pinhole may crop up. Where there was a pinhole on copper is where there was green corrosion there. Can those areas be cleaned up or do I un-sweat all those areas and then re-sweat them? There are a lot of those areas where over the years, sloppy soldering cause this green-ish looking corrosion to appear and some developed leaks.