Downsizing Pipe - Water Velocity, Pressure, etc....

[Chefwong]

I have a 2 pipe hot water system. Meaning one feed, one return .
The 1 Baseboard I am looking the 1st one off the boiler.

All my baseboards are piped 3/4.

On this baseboard, the feed and return are piped 3/4 already.
I am ordering a Runtal baseboard and they were advising strongly to go with 1/2" on the piping on the rear versus the speced 3/4".
We are using 3/4" Pex and was planning to just connect the 3/4" and *hang* the baseboard of it's cleats.

The Runtal rep was advising that while 3/4 piped on the sides is common (which I get....I just hate their trim covers), I was advised 1/2 is more common in the rear and to just use a adapter bushing. Or in my case, 3/4 PEX to 1/2" PIPE fitting . Am I technically downgrading the pressure of the system if I am going into a 1/2 pipe thread. What is the con of doing this or will it detract from the system ?

 

[hj]

I cannot see any benefit by doing it in 1/2", especially PEX, but since it is a two pipe system, every radiator is independent so you will NOT affect the "system's pressure", although you will probably increase the "head" pressure of that particular unit and thus reduce the flow volume.

 

[Sponsor]

 

[Chefwong]

Got it. Thanks.

They were advising on how they build it, if I went with 3/4 on the rear, it would increase the depth 2" more.
Long story as it was *just the same* to me, as the RO on where the stubs for feed, return are, it will still be 3/4" + hole for the feeds anyway - what is the big deal if the RO hole is 1/8" more. They were advising about depth in the cavity, etc. So I decided to let them build it in 1/2 and will just use 1/2IPS - 3/4 Pex adapter