1 inch return line

[CoryDude]

Just curious to see if anyone has first hand experiences with switching from 3/4 inch to 1 inch pump return lines. I'm rebooting my tank and current have 3/4 inch lines from my mag12 to the dt. But the new chiller I bought had 1" outlets and so I was thinking of upsizing.

just wondering if I'll see a large increase in gallons per hour if I redo all my return lines and use 1 inch piping.

[FireWater]

Not sure, Cory.

I would believe that a larger diameter would lead to less back pressure on the pump though. I can't figure out the math on a 1/4" increase in diameter.

[Dean]

Increasing the volume of water in your return line could have a negative effect on the pump if it is not sized for a 1" return and how ever many feet of head. If the outlet on your pump is 1" and the specs give you flow rated with a 1" return then it would likely benefit. If not then you could actually slow it down with a larger return by creating more head pressure.

I looked up the mag 12. 1200 gph and 3/4 inlet / 3/4 outlet. My professional opinion would be that you will lose flow due to increased head if you go to a 1" return. The chiller has a 1" outlet so that installation would not be limited to a 3/4" return which is probably the average size for return lines.

Anyway. Just my .02 cents. Hope it helps.

- Dean

[alton]

Remember if you are using barbed fitting they reduce your 1" to 3/4"

[Bill S]

Dean,

I don't think hydrostatic pressure works that way. For instance, it doesn't matter whether Canyon Lake Dam has 1 foot of water 100 feet deep behind it, or 10,000 acres of water 100 feet deep behind it - water doesn't compress, so the hydrostatic pressure (head pressure) is the same.

Math tells you that 1" will support almost twice the flow as 3/4". That being said, where ever there is a restriction, it will slow it down. But my motto is: Bigger is better.

[kkiel02]

Cory is your tank drilled for 1"return? Trying to figure out your system.

[CoryDude]

Remember if you are using barbed fitting they reduce your 1" to 3/4"

No flexible tubing for me Alton. I'm going with rigid PVC on the drains and the return.

Thanks John, Dean, Kevin, and Bill. It's been a while since I've calculated flow density using bernoulli's equation, but a larger diameter should lead to less pressure. But dean is right that the 3/4 inch outlet on the mag would limit the flow.

But my eventual plan is to go back to an external iwaki which has a 1" outlet. Kevin, the tank has dual overflows with 3/4 inch returns. I'm leaning to sticking with the current 3/4 lines based on y'all's feedback and then upgrade to 1" lines when I buy the new iwaki later this year.

[kkiel02]

So you are thinking about going 1" from the iwaki you buy to the chiller then y'ing it into two 3/4" correct?

[CoryDude]

So you are thinking about going 1" from the iwaki you buy to the chiller then y'ing it into two 3/4" correct?

Yeppers

[kkiel02]

I think that would work. As you probably know just try and not use 90 degree elbows unless you have to. I like the flex tubing so you won't have that problem. Your sharpest bend will be your bottle neck.