Head Loss?

[aldiaz33]

Well if my memory serves me right you will experience less head loss with a smaller diameter pipe than a larger diameter pipe. This is due to the difference of pressure. You will have less pressure using the 1inch pvc pipe rather than the 3/4 which in theory should give you more gph. The pump has to work harder to move water through the 1 inch pipe vertically than the 3/4 pipe. Dont know the specifics but I know this to be true.

You've got it backwards.

Reeflo has a good write-up on this topic. Below is an excerpt:


There are two elements that cause pressure requirements in your system; vertical lift and

“FRICTION LOSS”. Simply stated it is the pressure created by trying to squeeze large flows

through a narrow opening (think bar straw). There are two important aspects 1) It matters the

length of the narrow line (1” bar straw vs. 10” bar straw) and 2) Friction loss increases at an

increasing rate when either flow is increased or pipe is narrowed. The narrower the line the more

the pump has to work (think clogged ateries and your heart).

Minimize friction losses by using large diameter pipe. First determine the approximate flow rate

you want, and the total length of your pipe. The Friction Loss chart will allow you determine the

amount of extra “head pressure” will be added to your system due to the diameter of your piping.

(The size of the pump’s suction and discharge ports does not indicate your proper pipe size.)

Choose a pipe diameter that keeps your friction loss below about five feet per hundred feet of

pipe. Even if you have a section of small diameter pipe that you can’t change, as with a through

the wall fitting, it is still beneficial to use larger pipe on the majority of the run. It matter how much

wide pipe you use.Friction loss chart- The narrowness of the pipe increases friction loss in a

geometric manner.EXAMPLE: At 2700 gph using 1.5” instead of 1” pipe reduces friction loss from

97.75’ per 100’ to 11.73’ per 100’. A big reduction in “head pressure”

The chart can be found here: http://users.neo.myregisteredsite.com/0/1/3/11915310/assets/tips.pdf

Reeflo's recommended pipe size for flow can be seen below. This doesn't mean you will only get 600GPH if you use 1" pipe. It means that in order to achieve maximum flow/efficiency, you should use the recommended diameter pipe for the given flow rate.


PIPE SIZE FOR

RECOMMENDED FLOW


1" for 600GPH

1 1/4" for 1,200GPH

1 1/2" for 1,800GPH

2" for 3,600GPH

2 1/2" for 5,400GPH

3" for 10,500GPH

 

[DB junkie]

My .02..... I'm a nazi when it comes to pipe sizing. I won't bottleneck it, so would have went 1.5 then "T"ed to (2) 1".

I don't think you'll loose anything going from 1" to (2) 3/4" though, think there's more surface area on (2) 3/4......

 

[ShadowStryder]

In actualality I went from 1.25" down to 1" then tied into the 2x 3/4" Ys. Either way I believe it would have bottlenecked. Because using two Ts and 1" pipes I would still have tied into the 3/4" bulkheads. Figured the flow slamming into back of T would have hit head height harder than using two 3/4" Ys. Tried finding true 1" Ys like these 3/4" but no luck. And I contacted at least a dozen different online vendors and plumbing sites.

Wanted to enlarge the overlow bulkheads but after enlarging the drains it didnt leave enough room to increase the bulkhead size in the bottom of overflow.

Either way I am cant complain. I am pushing roughly 4K in flow which is more than I figured I would get with these return bulkheads.