PEX to feed hot water coil

Riles_3

I have a contractor that wants to run PEX instead of copper to feed a 100,000 Btu hot water coil. The run length is 80' one way. Feeding 180 degree water. He doesn't want to run 1" PEX.
He wants to know if he can run two supply lines of 5/8 or 3/4 PEX. I know from Appendex K of Wirsbo CDAM @ DeltaT of 20 degrees, 5/8 is <50,000 and 3/4 is 50k to 70,000. No problem with flow GPM 5 to 7 with each line.
Can you run two supply lines up and merge at coil? Then same size two lines back.
Thanks for your thoughts.

Gary Fereday

consider

That the connections on each end are identicle and the pipes are the exact same length. The end connections should be made with T's placed crosswise to their enlarged center outlet.[bull head tees 3/4x3/4x1/14]. All nipples and ells should be exactly the same on both parallel lines. You could get away with it. However again condider the cost and looks of this arrangement. Have fun bigugh

Riles_3

Thanks.

JIM F.

heres on that we fed 2 seperate manifolds with 1 " pex
4 1" pex lines from boiler room feed these racks- 2 air handlers and 2 garage heaters

Mark Eatherton1

Consider this too....

the pipes will "grow" 9.6 inches in overall length when going from 70 to 180 degrees F. As long as he takes this into account and locks the tube on one end and allows for expansion on the other he'll be OK. If he doesn't, he'll have a customer with a VERY loud piping system.

It does take some forethought to do it right.

In stead of piping it as Big Ugh has said, which will work if performed perfectly, consider piping the parallel brancehs in parallel reverse return fashion. John Siegenthaler wroten one of his very first articles about bull heading tees. He's against it and so am I. Remember, water is lazy and dumb. If it has to make up it's mind with a bull headed tee, it will never settle down to a stable flow pattern. But then again, you and I and the customer will probably never know the difference...

ME

To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"

Gary Fereday

And that

Is BRAINSTORMING thanks ME!

Eric

Commercial building?

Ceiling plenum?

Is Pex rated for plenums?

John T_2

Looks like

A First Co. air handler. Have you had any problems with their blower wheels not being true? Had a 4 ton that I just haven't been able to get a decent wheel from them. They ship out with a woobble to them. They've had three attempts at getting me a decent wheel. Darned frustrating!!

John Taylor

don_9

John

You too!I have that problem also,not only that but the
blower is so close to the coil that you dont get true
capacity either.check out the temp rise some time you will see what i mean.Or go back after a few years and see where the dirt's is at on the coil.

rick_2

why won't he run 1" PEX? SEEMS LIKE ALOT OF WORK AND MATERIAL THE OTHER WAY.

Riles

Thanks

Mark:

Thanks for the reverse return idea.

I got the contractor to see the light and do it right, he will be using 1" PEX. His biggest issue with 1" PEX was no QS20 compression fitting available. So I offered to come by the job with my expander tool and install the 1" ProPex Fittings required. Heck it is a chance to show him how nice the ProPex fitting is.

Hey, how's the radiant wall experiments?