Steven Edward Haun
Post Number: 145
|Posted on Wednesday, December 29, 2004 - 11:37 pm: ||
I have been searching the archives regarding the ideal size of copper tubing to use for a herms coil. 1/2" seems to be what most people use. However, I am confused. Is this 1/2" ID (5/8" OD) tubing or is it 1/2" OD tubing (3/8" ID)?
Post Number: 619
|Posted on Thursday, December 30, 2004 - 12:51 am: ||
The actual size is 1/2" OD and fittings (flare, compression, etc)are 1/2" when talking soft copper tubing. For copper sweat fittings you need 3/8" to fit over 1/2" soft copper. Hope this makes sense.
Post Number: 690
|Posted on Thursday, December 30, 2004 - 01:30 am: ||
I use 1/2" OD, which is actually larger than 3/8" ID, Grainger 3P672 is about $38 for 50 feet, but you probably don't need 50 feet, quite a few HERMSers use 25 foot coils. 3/8 OD is too small, the increased head losses mean low flow rates.
For sake of clarity, always refer to the OD size when discussing copper tubing.
Post Number: 131
|Posted on Thursday, December 30, 2004 - 07:13 am: ||
Keep researching ! It is not intuitive.
In fact it is downright confusing till you get the hang of it.
Pipe & Tube have different fittings:
Compression & Flare for tubing
Sweat and NPT (thread) for Pipe.
1/2" soft copper tubing, as used for herms coils is actually 1/2" O.D.
1/2" copper pipe is 5/8" O.D. - Go Figure !
I.D. varies between 0.527 --> 0.569" dependent on type.
My Herms uses 50' of "1/2" tubing. I connect to my "1/2" pipe fittings with a 1/2" compression to 1/2" NPT adapters.
(Message edited by joez8 on December 30, 2004)
Steven Edward Haun
Post Number: 147
|Posted on Thursday, December 30, 2004 - 01:51 pm: ||
My entire system (hoses, full-port ball valves, quick disconnects, couplings, pipe, etc) is 1/2". If I use 1/2" OD copper tubing for my herms coil, won't that have significantly higher resistance than the rest of my system? Is that a problem or do you have to decrease your flow so much to prevent compacting your grain bed that the increased resistance of the herms coil is insignificant?
Post Number: 1626
|Posted on Thursday, December 30, 2004 - 03:28 pm: ||
Don't sweat it, Steven. The relatively small difference in diameter between 1/2 in. I.D. pipe and hose, and 1/2 in. O.D. copper tubing for the recirculation coil is not going to cause problems.
Post Number: 693
|Posted on Thursday, December 30, 2004 - 06:47 pm: ||
Steven, you already have several points of restriction tighter than the .436 ID of 1/2" OD tubing. Your QDs have a smaller ID, any barbed fitting does. Besides, going larger than 1/2" OD tubing is actually less efficient in a coil of reasonable length, because of the ratio of volume (per foot of tubing) to contact surface area.
Belly Buster Bob
Post Number: 1953
|Posted on Thursday, December 30, 2004 - 10:57 pm: ||
just to toos a curve...I use 3/8 tubing. Pipe can also be used for a coil...fill it with sand and bend away