Could this be right?

scott markle_2

Rethink the .6 part of it. 120 is only half the story. it's about delta, assuming 20 deg. delta .6 gpm = 6000 btus. If your spacing is 6" and if all 226' of your tubing was on the floor. 226x.5 =113 sq.ft of heated floor. let's be generous and give you 30 btus/sq.ft 30x113= 3339 or .33 gpm at 20 deg. delta.

GPM=BTU/500X∆T hence 3339/10,000=.33

Try and keep those 5/16 loops under 200 or so and get your heat loss under control and your head pressures should be more reasonable.

Dan Sedens

Upunor pressure drop calculations.

I am calculating pressure drop in a 226' loop of 5/16'pex tubing. The flow rate is .6gpm and I have a supply temp. of 120. I calculated the pressure drop to be 32' head. Could this be right or am I doing something wrong? From my CDAM I am using a factor of .14171/ft. I forgot to mention that this is for 100% water.

Please help.

Thanks.

Dan Sedens

Doug_7

Pressure drop calculations

That would be correct.

See attached Viega Tech Datasheet - page 2.

A GPM of 0.6 is too much flow for 5/16" tubing. That requires a pressure drop of 15 psi.

Doug

scott markle_2

oops

.33 not 3.3

Dan Sedens

Thanks for the help

Guys,

Thanks for the input. I was trying to run a 10 Delta. Works much better with a 20 Delta. All is good now.

Again, Thanks for the help.

Dan Sedens