Posted By heatoftheearth on 12 Jun 2010 10:48 AM
Looby, I have used that spreadsheet for all my climatemaster installs,
about 15 and counting. It has been dead on every time, verified with
a flow meter.

I saw what you mean about the AF correction factor. Didnt seem right
to me either ....

When a program's output "doesn't seem right," I want to know why.

Every source I've seen, including CM's Flow Center Installation Guide,
shows significant increases in dynamic head (compared to water) for
methanol and ethanol. There's nothing "company specific" involved
here -- it's jus' plain physics -- and the 1%-3% AF correction factors
displayed by that spreadsheet are jus' plain wrong.

Maybe the script "fixes up" the final results by applying an opaque
"base pumping penalty" or some other invisible skullduggery -- but
I've been flogging bits for enough years to distrust the final output
when the intermediate results are certifiable nonsense.

Again, I dont think the recommended flow rate for the 026 are 7 and 8 gpm.
IMO its is 6gpm.

I concede, you are correct. I don't know why the Tranquility27 spec
sheet lists 7 and 8 GPM for the TT026 since they're inconsistent
with other CM recommendations (in the case of the TT026, only):

http://www.climatemaster.com/downloads/97B0015N01.pdf

"Loop Circuiting - Loops should be designed with a compromise
between pressure drop and turbulent flow (Reynold’s Number) in
the heat exchange pipe for heat transfer. Therefore the following
rules should be observed when designing a loop:

• 3 gpm per ton flow rate (2.25 gpm per ton minimum). In larger
systems 2.5 to 2.7 gpm per ton is adequate in most cases.
Selecting pumps to attain exactly 3 gpm per ton is generally
not cost effective from an operating cost standpoint."

Posted By riggerjack on 12 Jun 2010 09:53 AM
... so i thought of this like a simple dc curcuit. so 2 parallel 10 ohm
resisters result in a circuit resistance of 5 ohms.

It's exactly analogous to a DC circuit, except that the resistors aren't quite
linear. Flow resistance (head) increases with increasing gpm (analogous
to a nichrome heating element, whose resistance increases with current).

For a given pressure drop (supply voltage), you can increase gpm (amps)
by adding more parallel loops (load resistors).

... so if i added another 800' 3/4" loop, i would recalculate resistance
with a flow of 2.66 gpm, and add the results, right?

'zactly. But be careful to maintain enough flow in each branch for
adequate turbulence -- with three branches, it might be wise to go
for 3 gpm per branch (9 gpm total) to keep Reynolds# above 3000.

ok. I think that's fairly settled then. next couple of questions:
i know that you pros use HDPE throughout, as a underground leak is a horrendous waste. but i have a solid pipe for my loops, and all the splicing will be inside my utility room. i'm much more comfortable wirking with PVC, as well as better availability and not needing specialized equipment. is there a good reason for a DIYer like myself to use PE instead of PVC? I could just use a brass barbed connector, and convert over to PVC. Is there an issue with PVC and antifreeze?
i'm doing this on my own, so the more data i can gather when trying to see what's going on the better. what guages do you recommend? i was thinking ewt & lwt temp guages, pressure guages on each side of the pump(s), and trying to find some kind of flow guage. anything else i should think of adding? maybe a filter? hints as to sourcing would be nice, too.