Basement Sump Planning Need Input

No real need. 1" should be the smallest though. Very easy to run 1" to the tank with the bulkhead being the only restriction. If your bulkhead is a barbed fitting... then it is going to be a BIG restriction. Change it out for a threaded and attach over the fitting, not in it. Barbed fittings are very restrictive. Take a look at my Herbie write up to see what I mean.

http://www.3reef.com/forums/i-made/my-herbie-overflow-write-up-pics-beware-60239.html

 

Not everything is hooked up yet, however I did run my drain line (1.5") and one part of my return (1"). Even at 500gph I think I would be content although I would like to be closer to 750gph. The Bulkheads for the drain and return are both dual threaded/barbed fittings. I dont really want to have to change them if I do not ABSOLUTELY have to because the way the tank sits against the wall and it is a Mega Overflow its very hard to get to the bulkheads and I do not want to encounter any leaks after re seating new bulkheads. Do you feel that it is a necessity to change them? I actually may HAVE to use the barbed portion of the return fitting to hook into the pvc somehow because the holes drilled in the stand where the bulkhead comes through isn't large enough to be able to get pvc around the top threaded portion.

 

It's not a matter of go-no go. See how it works for you. Try to eliminate as much restriction/friction as you can.

The overflow does not matter. The return does, and I get what you mean about the stand. tings do get in the way.

Changing bulk heads is not that big of a deal. I had limited room too and had to get my arm down the overflow box to make sure there was nothing on the bottom to cause a leak, but you can do it.

No big deal though. Hook up your stuff, measure what you have, and see where you are at. Go from there.

 

Any suggestion on going from 1" pvc to 1" vinyl tubing? Im guessing add a barbed fitting to the pvc?

 

That is probably the easiest, however...

Give serious thought to using flexible PVC. I used it extensively in my build out and, while expensive, makes complex PVC plumbing jobs 10x easier and has the added benefit of removing a lot of hard elbows and 45s. It fits right in to all standard PVC fittings.

The only difference in using it vs. standard PVC is the glue. You need to use something like Christy's Red Hot glue (which is blue, btw). I use that now for all my PVC joints, flexible or not.

EDIT: I just read down and saw you've already run rigid pvc. Give some thought to using flex PVC instead of vinyl tubing. Less restrictive for flow and you should be able to buy short lengths at a hot tub store.

 

Try to stay away from barbed fittings... they neck down the I.D. significantly. I used threaded or slip and ran my line over the fitting.

 

Hey, have you ever seen data on exactly how much friction is saved, using flex over rigid? I'm just curious. There still is a direction change and friction, but I'm sure it is much smoother.

 

You had to ask...

Head loss due to bends is related to velocity of the fluid and the radius of the bend in relation to the radius of the pipe. Assuming you keep velocity the same, the head pressure is a linear relation to a coefficient derived from the radii mentioned above.

The actual formula is:

H = .5 * K * V2/g

H = head height
K = the coefficient I mentioned - this is a logarithmic relation that's pretty complicated to figure out. I've seen some tables that list these for various pipe/bend radii
V = velocity of the water (V2 is velocity squared)
g = acceleration due to gravity = 32.2 ft/sec2

Some notes:

- I had always heard that each 90 fitting added to a pipe yields a 1.5 foot increase in head pressure. This is a flawed estimate since head pressure has a square proportion to velocity. So double the velocity through the pipe and the head pressure quadruples.

- To make the math simple I'll give an example of 1200 gph through a 1" pipe. This yields a velocity of about 8 feet per second.

- The K value for a typical PVC fitting (bend radius = pipe radius) is 1.98.

- Using the above values:

H = .5 * 1.98 *(8*8 )/64.4 = .98 feet

So each 90 degree elbow in a 1" pipe at 1200 gph adds one foot of head height.

Now...

If you change out the 90 degree elbow for a flex pipe with twice the elbow's bend radius, the coefficient (K) drops from 1.98 to .29. That means the head height changes from about 1 foot to .144 feet or about 1 3/4 inches.

Take the 90 bend radius out to 5x of the pipe radius and the coefficient (K) drops to .14 which takes the head height increase to just under one inch.

TL,DR: A 90 degree elbow adds 14 times the head height that a wide radius bend (5x pipe diameter) does.

 

There were quite a few complications, and I didn't want to change the bulkheads already on the tank. Which I had assumed were 1.25-1.5 and 1" (drain/return) however I was completely wrong, and the inner diameter on the return was 1/2" and the id on the drain was 1". So I plumbed the whole thing from the pumps 1.5" outlet to the tank with 1.5, then had to reduce to 1". I ended up using a barbed end and using hose to the bulkhead. The drain is also a barb from 1.5 to 1". Sucks, but it works wide opened. In theory my GPH should be 800-1000 which the 1000 is unlikely considering I am using lots of 90's and long runs of pvc.

But it is all working.

 

Been a long time since fluid flow class. I pretty much knew the obvious answer... but that was actually what I was looking for. Thanks for the memories.