Check valve placement?

Our well went dry and I'm scrambling to get a rainwater collection system together. Rather than put large collection tanks below our house, spoiling the natural view, I've hidden a smallish (1100gal) tank there to collect the water, and have a submersible pump w/float switch driving about 300' of 2" pvc pipe up about 30 vertical feet (fairly gradual slope) to my storage tanks.

I'm feeling like I need a check valve in that line to keep 300' of water from draining-back down the pipe when the pump shuts off--the pump already did a bunch of work to get it that far, ya know?

I've got a 2" swing-check valve to stop flow-back, and am wondering if it makes any difference where I place it? One idea I have is that if I place it at-or-very-near the tank, maybe the weight of 300' of water works on the gasket and causes premature failure. And it may not rain again for a long while--will the valve "stick" shut... Another idea is that I place it up by the tanks, where it stopples less water, and it still functions (the pipe holds water) owing to vacuum in the line.

Or maybe I'm obsessing over over a little bit of water (electricity actually) and don't need a check valve at all?

TIA for any thoughts--I'm new to this stuff but being forced to learn fast!!! And out in the "extreme country" where help is nowhere to be found!!!

Oh, here's a link to the valve I have if anyone's curious...

http://www.clearpvcpipe.com/index.asp?PageAction=VIEWPRODGROUP&ID=18

MaxBlack said:

submersible pump... I'm feeling like I need a check valve in that line to keep 300' of water from draining-back down the pipe when the pump shuts off

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You're submersible pump already has a built in check valve, you might consider a flow restricting sleeve to direct the water past the motor so it doesn't overheat.

Rancher

Rancher said:

You're submersible pump already has a built in check valve...

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Thanks Rancher, but... no it does not.

Put your checkvalve just after or on the pump, and you dont need a 2" - use a 1" brass or bronze disk or ball type. Surplus center has a stainless steel
1.25" for 13$ - top quality mil spec. Flowmatic is good also.

The clear valve is for pools. It will fail early on. Don't use it. Dont use any swing type check valves. Interesting source for clear pipes and fittings, however.

MaxBlack said:

Thanks Rancher, but... no it does not.

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Really? They make submersibles without check valves? What brand/model do you have?

Rancher

Hmmm, *most* submersibles that I found don't have integral checkvalves. My pump is a Multiquip 2040T.

Raucina I wanted a 2" check valve, and a swing check valve at that (as opposed to a spring) to absolutely minimize backpressure in the system and maximize gpm output. We have some gully-washer-type rainstorms here sometimes.

MaxBlack said:

Hmmm, *most* submersibles that I found don't have integral checkvalves. My pump is a Multiquip 2040T.

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Ahhh, ok I was thinking deep well submersible, what that really is, is a sump pump and yes you're right they don't come with check valves, put the valve as close to the pump as possible, and a swing gate check is fine when mounted vertically.

Rancher

Rancher said:

...what that really is, is a sump pump ... put the valve as close to the pump as possible...

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Yeah, that's right I'm using a short (45") storage tank as a sump, and the Multiquip is actually a "trash pump" just-in-case any junk (leaves/twigs/nuts etc) gets into it.

I'll install the valve in such a manner that it's easy to replace if it should happen to fail. Thanks!

Are you sure that sewage pump will push 30 feet vertically? A lot of them won't go much beyond that and aren't moving much water at that level.

bob...

Indeed the performance curve for the Multiquip pump says it will do 40gpm at 30 feet (I did my homework). I will be happy w/20gpm so unless I mis-measured somewhere it oughta work. Very heavy-duty pump...

Now we just need some bleeping rain here!