# 1 inch transportation pipe ok?

Discussion in 'General Discussions' started by nc73, Dec 15, 2018.

For 2 vertical loops 200ft deep 3/4, would it be ok to use 1 inch transportation pipe? Supply and return that is. It’s what I have. I will get 1 1/4 if I have to.

How long is the header run? Flow rate in GPM? What model pump?

Run is about 35ft, flow rate will hopefully be 7.5 gpm. i have the 26-99 with 3 speeds, flowcenter.

came up with 35 for head with 1", 1 1/4" - 32 head

Guess I will see if they have 1" pipe instead of 3/4 for the loops

How did you calculate system head? Is this a 2.5 ton heat pump?

If it is only 35' from the loops back to the house, why not run the 3/4" loops all the way back to the unit and make your header there? That way you are only pushing 3.75 gpm through a 3/4" pipe rather than pushing 7.5 gpm through a 1" pipe.

You shouldn't be anywhere near 30+ ft of head pushing 3.75 gpm (7.5 gpm / 2 for a parallel loop) through a 3/4" x 470' loop ((200' + 35') x 2) unless you are pumping molasses. What if any anti-freeze will you be using (type + concentration %)?

A 26-99 is only good for a maximum of ~25' head pushing 7.5 gpm.

Yeah 2.5 ton using the climatemaster spreadsheet. 15% methanol. I must not be any good at deciphering the spreadsheet, been changing numbers here and there and still get around 32-34 unless i switch to 1" loop pipe (19head)

I know why, it's because I'm trying to match my heat pump to their models, and the pressure loss difference is probably what's screwing things up. I went to a 2 ton model and head came to 21. switched to a 2.5 model and came up with 25 with 1" trans pipe.

If you are using the Climatemaster software for another brand of heat pump, I would focus only on the correct tonnage, and gpm as inputs for Unit #1. Ignore Unit #2 and #3. Assuming you run the 3/4" loops all the way back to within 5' of the unit, you would have 10' of 1" hose kit, no inside supply & return piping, no outside supply & return piping, Circuit Piping = 0.75" pipe size, Design GPM/ckt = 3.75, 470 ft of pipe. All you would use from the program is the Circuit Piping total ft of hd calculation and then add that to your heat pump manufacturer's unit head loss (should be in the manual somewhere) at rated flow and add in a couple ft of hd for fittings for total system head.

Since, I assume, your loops will be in parallel, you only have to calculate head loss for a single loop at half the total system flow.

I would guesstimate your circuit piping head loss to be around 10 ft of hd. I would run the numbers, but I'm at home and don't have Excel on my home computer.