# Water pump for cistern



## wrx-snowdrift (Jun 24, 2016)

I'm looking for a pump to pull water from my unused cistern. I'm planning on rerouting the gutters so that I can collect rainwater into the cistern and then use that for watering plants but I need a way to get it out of there. I know I could use an electric submersible sump pump but I like the idea of some of these small gas powered pumps, I feel I would get more utility out of them. Menards has a nice Honda on clearance for what seems like a screaming deal, I've also been looking at the Generac but I would guess the Honda is superior.

The cistern is about 12ft deep so I'm wondering how well these little pumps will handle that amount of suction.
Anyone else done something like this before?

https://www.menards.com/main/plumbi...431297349-c-8673.htm?tid=-6092022382345109461

https://www.menards.com/main/plumbi...431298030-c-8673.htm?tid=-4666770191685955237


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## blades (Jun 24, 2016)

I had something like a 8hp Honda powered 1800 gph pump back in the 80's no problem pulling 12ft plus at full bore or at half speed, 4" discharge.
I would stick with Honda vs the Generac ( customer service is not their strong point)

Be aware than from the looks that neither is self-priming


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## wrx-snowdrift (Jul 3, 2016)

Alright, I went with the Honda, picked up some nice Banjo quick couplers for the hoses. Very happy so far. 
So my next question is if I wanted to use the pump in an "on demand" application where the pump would be continuously running but flow would be switching on and off (like putting a spray gun on the end) how would I go about installing a relief valve so the pump isn't water hammering? If I install a relief valve on the pressure side wouldn't it just spray water out the relief valve?


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## blades (Jul 3, 2016)

relief valve output could be routed back to the cistern into a baffle box to keep from developing a vortex from the flow.


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## Del_ (Jul 3, 2016)

I would have opted for a 1/2 to 1hp ground level electric pump. Switches are available to cut the pump off at low water levels or if the pump loses prime. Also nice about an electric pump is that timers can be used to cut the pump on and off. I had a wind up type of times where I could set it for 1 to 12 hour run time. I just had to turn the pump on and it would run for the time set then switch off.


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## wrx-snowdrift (Jul 3, 2016)

blades said:


> relief valve output could be routed back to the cistern into a baffle box to keep from developing a vortex from the flow.


That would certainly work but it sounds like a lot of added plumbing and work. Maybe easier to just deal with never closing the nozzle unless the pump is off.


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## wrx-snowdrift (Jul 3, 2016)

Del_ said:


> I would have opted for a 1/2 to 1hp ground level electric pump. Switches are available to cut the pump off at low water levels or if the pump loses prime. Also nice about an electric pump is that timers can be used to cut the pump on and off. I had a wind up type of times where I could set it for 1 to 12 hour run time. I just had to turn the pump on and it would run for the time set then switch off.


Yeah electric would have been the easier and cheaper but at the moment all I'm using it for is filling a 250gal cage tank that I move around with the tractor and loader to water a dozen trees I just planted. Also, I like having options and versatility. With the gas one I can pull water from our creek, I can also use it for watering offsite locations, I'm planning on planting about an acre of my lawn into native short grass and forbes so I might use the pump hooked up to a 250gal cage tank and a sprinkler to help speed things along and if the power ever goes out I have a back up for the sump.


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## 066blaster (Jul 3, 2016)

not sure what size oulet pipe or hose you are using , but you could put a valve in the oulet pipe re-routing it back to the cistern , keep it half open at all times. when you close your spray wand everything will go back to the cistern.


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## wrx-snowdrift (Jul 3, 2016)

066blaster said:


> not sure what size oulet pipe or hose you are using , but you could put a valve in the oulet pipe re-routing it back to the cistern , keep it half open at all times. when you close your spray wand everything will go back to the cistern.


That would also work, and be fairly simple.

Maybe I'm overthinking this (I tend to do that....a lot). When I did commercial spraying we'd fill the sprayers with essentially larger versions of this pump and we'd close the valve all the time with the motor still running and they never had problems and I don't remember any sort of relief or bypass valve. I just worry since the manual said not to. Here is what the manual says *"Beware of water-hammering: Do not allow any vehicle to run over the delivery hose. Do not close the delivery valve abruptly because water-hammering may occur. This may result in heavy damage to the pump."*
So maybe closing the valve slowly is the key so that its not such a sudden change??


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## 066blaster (Jul 3, 2016)

wrx-snowdrift said:


> That would also work, and be fairly simple.
> 
> Maybe I'm overthinking this (I tend to do that....a lot). When I did commercial spraying we'd fill the sprayers with essentially larger versions of this pump and we'd close the valve all the time with the motor still running and they never had problems and I don't remember any sort of relief or bypass valve. I just worry since the manual said not to. Here is what the manual says *"Beware of water-hammering: Do not allow any vehicle to run over the delivery hose. Do not close the delivery valve abruptly because water-hammering may occur. This may result in heavy damage to the pump."*
> So maybe closing the valve slowly is the key so that its not such a sudden change??


most sprayers have a relief in the form of jet agitation . when you close your wand or boom valve it all goes to the agitation in the tank. you dont need a lot of flow, but most pumps require some.


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## wrx-snowdrift (Jul 3, 2016)

066blaster said:


> most sprayers have a relief in the form of jet agitation . when you close your wand or boom valve it all goes to the agitation in the tank. you dont need a lot of flow, but most pumps require some.


Right but I was talking about the pump on the water truck that we would use to fill the sprayer. We'd put a 1,000 gallons into the sprayer and mix our chemical in the inductor and then when the sprayer was full we'd close the valve and then shut the pump off because we didn't want any spray to back wash into the hose or water truck. I'm guessing it wasn't real good for the pump but I never had any issues.


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