Overflow rated at 3000gph....is a pump rated at 2328gph too small?

[PotRoast]

I have two overflows rated at 3000 gph (combined)

It was suggested my return pump from the sump be just less than 3000 gph.

The pump I have on order is rated at 2328gph.

Will this pump work?

Or do I need a bigger pump? If I get a pump rated higher than the overflows I understand I can tee the return and divert some water back to the sump.

 

[clown-lover]

Sure it will work but you'll have to put ball valve(s), gate valve(s) on your overflow to sump line to slow it down. Basically you have to match the amount of water going down to the amount going up. Otherwise one or the other will flood.

 

[dolfans1]

What type of overflow do you have?

For a drilled tank with standpipes, the rated flow is the maximum, and is dependent upon the water level and the standpipe height. It becomes self-regulating this way - as the water level drops in the tank, the drain flow also drops, until the water level goes below the standpipe U-tube height, at which point it stops draining (this would happen if there was a power failure and your return pump stopped). You just don't want a pump that is returning water faster than it can drain from the overflows, so in your case you would be OK. No need to use valves to balance the flow.

 

[Ace25]

Sounds like you have a big tank. Also, remember the pump loses power the more vertical lift is added. As an example, a Mag18, 1800GPH pump, puts out 1350GPH at a 5' lift.

I agree with dolfans1.. as long as your return pump isn't stronger than the max overflow rating you should be fine. Ya, you may have some noise issues from your overflow like clown-lover mentioned, but there are multiple cheap ways to fix that issue.

 

[PotRoast]

I have a 240 gal.

I have a drilled tank.

One of the things mentioned was the height of the stand pipe. Is there any way to determine the proper height (besides trial and error) of that pipe? Maybe a mathmatical formula? (I don't know.)

I want to try to avoid multiple floodings while testing various lengths of standpipes. (with the power off, simulating power failure)

Thanks for your help.

 

[Sploke]

Sure it will work but you'll have to put ball valve(s), gate valve(s) on your overflow to sump line to slow it down. Basically you have to match the amount of water going down to the amount going up. Otherwise one or the other will flood.

As long as your overflow is properly set up, this shouldn't be an issue. With a standpipe or overflow box set to the appropriate height, the water that overflows out will only equal the water thats being pumped in.

 

[Sploke]

I have a 240 gal.

I have a drilled tank.

One of the things mentioned was the height of the stand pipe. Is there any way to determine the proper height (besides trial and error) of that pipe? Maybe a mathmatical formula? (I don't know.)

I want to try to avoid multiple floodings while testing various lengths of standpipes. (with the power off, simulating power failure)

Thanks for your help.

Its mainly trial and error. I try to get it as high as possible in the tank. The same amount of water will overflow regardless of standpipe height, the height will control the water level in the tank.

I'll try to clarify. Your pump puts out a given amount of water from the sump to the display tank. Say the water level needs to be 1/4" higher than the standpipe to reach an equilibrium flow. Whether your standpipe is 5" off the bottom or 20", that 1/4" over the standpipe will always be the equilibrium (not precisely, but the change is so small its negligible for our purposes). So, I generally set the standpipe about even with the bottom of the plastic trim on the tank. That way, the water level is just higher than the trim so there's no air gap seen at the top of the tank.

 

[clown-lover]

As long as your overflow is properly set up, this shouldn't be an issue. With a standpipe or overflow box set to the appropriate height, the water that overflows out will only equal the water thats being pumped in.

Only if you want to hear a toilet flushing constantly. Or at least thats the way it was with my unit. And that was with the whole silencer garbage and everything.

 

[Sploke]

I've used a durso standpipe, a stockman standpipe, and a hofer gurgle buster on different applications, all of which worked fairly well for me, and I'm pushing about 850gph through a 1" overflow. It practically syphons, maybe thats why its quieter. I use the HGBs on my fw overflows though, and I really like how well they work.

 

[dolfans1]

My overflows are pretty quiet, and are rated at 1200 g/hour (and I'm probably doing pretty close to that). As sploke said, it's mainly trial and error. I've also found that using filter bags in the sump quiets the sound of the water a lot.