need to know flow rate from drain line.

[silentshaw]

the drain line is 1" pvc with 20" of water above the drain. it will be draining 3' into the sump.
i need to know how much flow this would produce. so i can purchace my return pump to compinsate equaly.
thanks for you help.

 

[hurt]

I believe each 1in. bulkhead is capable up to 500gph. You don't want to buy a pump that can do equal to or more than your overflow. The overflow should be rated higher than your return pump. But, when you buy your return pump you must factor in the height of your return line and any 90' turns in the line or T's.

 

[6stokes]

Sorry to jump in here, but someone explain to me why you would want less pump rated gph than the overflow rating? Wouldn't that cause the sump to overflow or do you valve off the water being siphoned to match? If that's the case, then why can't you buy a bigger gph pump and valve down the flow? That way you would always have more flow if needed later.
I'm not disagreeing because I have heard this before, I'm just interested in doing a sump in the future.

 

[thedj]

I have about the same setup and I think I have the RIO 1400. I think its about 375 gph. The overflow box will not overflow because it only can get as much water as the pump puts out.

 

[6stokes]

I still don't understand. The overflow works on siphon and water seeks its own level, therefore, if you have a sump below the level of the overflow, it will keep overflowing until the main tank drops below the inlet of the overflow tube. If the intake is located at the bottom of the tank, then the tank will empty.
Anyway, my question was about the sump overflowing not the overflow box overflowing.

 

[pyro]

I follow ya strokes. I would say get a pump rated higher, and then divert the excess flow off with a T and ball valve combo or something similar.

 

[squidd]

There is (or shoud be) a "stand pipe" in your overflow box that "sets" the water level that can drain out of your tank...OR...
The "teeth or edge" of your overflow box limits the level of water than can drain from your tank...
When water drains below the standpipe or "edge" of the overflow box it stops draining...It's NOT (Nor should it be ) a "direct" siphon...
So what ever "flow rate" your overflow can remove (600gph - 1") you will want a pump that "DELIVERS" slightly less than that "TO" the tank...
Most likely You will have to purchase a pump that is "rated" higher than your overflow...because the "actual" amount the pump can deliver to the tank is lowered by "Head Pressure" and pipe diameter and elbow restrictions...

 

[squidd]

6stokes...
You may be confused by the difference between a "drain" and a "siphon"...
Here's a pic of a HOB overflow showing the difference between "drain" and siphon...and why the water will stop flowing in a power out situation...

 

[squidd]

Originally posted by 6stokes
... If the intake is located at the bottom of the tank, then the tank will empty...

Correct...DON'T DO THAT....:nope:

 

[6stokes]

Okay, sorry I'm so ignorant here. I understand everything you guys are saying, but if you get a pump that is rated lower than the drain rate, then why doesn't the the stand pipe draw air when the tank water gets below the level of the teeth in the overflow box? A lower rated pump will not return the water as fast as it will drain from the tank, hence my confusion.
What am I not getting here guys? Someone's going to have to draw me a picture I guess. I appreciate everyone trying.
And thanks Pyro, at least someone knows where I'm coming from.

 

[squidd]

I think maybe the confusion comes from the terms "Rating" and "Actual"...
You want the pump to return (actual) "Less Than" the overflow can take out (also actual, but based on rating)...
If you return more than (actual) the overflow can take out (actual) the tank will over flow...
If you return less than (actual) the overflow can take out (actual) it will not overflow...
Overflow "Actual" and "Rating" will be similar, because it is a "Drain"...
Pump "Rating" and "Actual" will be different because of head pressure, line size, elbow and outlet restrictions...and you may need a higher "Rating" to get the proper "Actual" flow you want....
Does that help any..??
why doesn't the the stand pipe draw air when the tank water gets below the level of the teeth in the overflow box?
It does...and the water stops, slows or matches flow (draining)...Actually the water level in the tank stops at the overflow box teeth level and the water "IN" the overflow box stops at the "Standpipe" level...(which should be slightly "lower" than the overflow box teeth level...)
See "picture" above...

 

[6stokes]

Bingo! Your last paragraph expains it. I just didn't think you would want the drain pipe to start and stop flow. Doesn't that create sound? So why couldn't I buy a bigger pump delivering rated or actual at more than the drain rating if I controlled the flow with a valve? That way, I could always use the additional flow for something else in the future if needed. Does it harm the pump to restrict flow after the outlet?
Thanks for putting up with me Squidd!

 

[hurt]

I should of stated this setup is for a sump below a DT. With the overflow above the sump, the DT H2O level will remain constant. The only place you will see fluctuations through evaporation are in your sump. If you get a return pump that is rated higher than your overflow rating, you will pump too much H2O up to your DT and overflow the DT because the overflow is rated lower than your return pump and can't handle all the H2O. The return pump rating must also caluculate in the backforce of moving up, 90's, T's, which all slow the output of your return pump.

 

[6stokes]

Okay, it all makes sense now, but can I valve off a higher rated pump without any problems?

 

[badkharma]

Although not ideal, you can. A gate valve works the best, and many have used ball valves with similar results but more fine-tuning required. Make sure you restrict the flow on the output side of the pump, never the intake side. Correct me if I'm wrong, but I have heard it's better to restrict the pump output than the drain input - I don't know the reason, it's just what I remember. I'm am currently setting up a 120 with a 1.5" drain and a sump - I'm using a sequence 750 as a return. I will most likely have to restrict the return line to slow down the flow a bit - the pump will probably out do the drain.
As for the other way around, your drain should never out do your pump, because if you set it up right, the tank will drain at the rate of the pump's output, regardless of hole size - to the maximum drain capacity, of course.

 

[tapeworm]

I have a 210 with two 1" drains. I have a 2400 GPH pump running full blast.
I noticed that there is a certain balance there. If your water level is too low, the pump will out do the drains. If the water level is higher, than there is a balance.

 

[6stokes]

Thanks everyone. I appreciate all the knowledge. :yes:

 

[guitarded]

hmm... i feel sorry for the original poster. his thread got totally hijacked!

 

[6stokes]

True, but the original question was answered and maybe he learned even more than he bargined for.
Isn't that why you read these?

 

[squidd]

Yep...:yes: and Yep...