water pressure

[tow653]

We have place out in country with no electricity. We use a 1/2 hp submersible pump to water plants,off a generator. currently pumping through 200' of 5/8 hose,with probably 30' of lift. We get a pretty good stream of water but not great. Recently put in new flower/plant garden that I'd like to water with a sprinkler,but not sure if enough pressure. Question is,if I reduce down to 1/2" hose will that increase pressure enough to run sprinkler? Thanks, Tim

 

[speedbump]

No, it will decrease your volume and pressure. The smaller the pipe, the more friction loss you will have.
Friction loss chart: Friction Loss Chart - Helpful Information - PumpsAndTanks.com

 

[Carl_NH]

Buy some 3/4" poly pipe or 1" and run this to a manifold and valve at the garden.

Also assume you have a bladder style pressure tank and switch? If not I would install one of these - you can run w/o the tank but it would be better to have a tank to shut off the pump and or prevent an overpressure situation.

You can make a manifold setup for sprinklers around the perimeter of the garden or use soaker hoses in each row off a manifold as another option.

 

[Little Red Tractor]

Buy some 3/4" poly pipe or 1" and run this to a manifold and valve at the garden.

Also assume you have a bladder style pressure tank and switch? If not I would install one of these - you can run w/o the tank but it would be better to have a tank to shut off the pump and or prevent an overpressure situation.

You can make a manifold setup for sprinklers around the perimeter of the garden or use soaker hoses in each row off a manifold as another option.

If you run a sprinkler head, I suspect that with the lift and length of run you have you'll probably burn out the pump unless you add that pressure tank--even if you go to 3/4 or 1" poly.

 

[tow653]

Should have been more clear with setup. Pumping from a lake,using 1/2 hp pump,200' of 5/8" garden hose hooked to pump,running pump with gas generator. Any sugestions on how to get enough pressure to run a sprinkler appreciated.

 

[radioman]

I think you might want to check your generator output first. If you have a 1/2 hp pump- look for the wattage or amps and google on line for running watts. then the starting amps for your particular pump. you might only need roughly 1000 watts for 1/2 hp pump but could easily double or triple the starting watts depending on efficiency of your pump. A 1000 watt generator might not be enough for starting amps of pump. Once you are satisfied with wattage usage of pump/genset combo, then you might want a bladder tank in between to have a more consistent pressure as last retort.

 

[Carl_NH]

The problem is your 5/8 hose is restricting the flow - you need a bigger line.

Put in 1" poly and manifold at the garden where you would need to install your sprinkler set up. Are you talking about the lawn and garden oscillating sprinklers that water 30 x 50' area or are you installing several tripod type rotary heads?

Your 1/2 pump at 30' of lift is probably capable of 12 GPM so I would install 1" main line for the 200' run, then a manifold at the garden to feed your sprinkler set up.

The pump will draw about 15 amps starting and probably 6 amps running (240 V) so your generator should be 3500 Watts size at least for this application.

Your pump will run and create pressure without a bladder tank, but if you draw in any debris from the lake and clog your sprinklers this could reduce the flow and in the end burn up the pump (no flow). For these reasons a tank and switch is suggested, also a filter on the output to the sprinklers will save you aggravation of cleaning them out from pulling in debris.

 

[speedbump]

also a filter on the output to the sprinklers will save you aggravation of cleaning them out from pulling in debris.

Rather than a filter, I would put the pump inside a lake strainer. This will protect the pump and the heads.

 

[RobertN]

Totally too small of hose, with unknown but probably poor friction coefficient. So you have huge friction loss.

Second, you lose at least 15psi just from head pressure(0.433/ft of elevation).

In this case, consider:
- Run plastic pipe from the pump to your distribution point. I would not go smaller than 1"; I would start with 1-1/4". It is cheap in 20' sticks at John Deer Landscape, Home Depot etc.
- On the end, put a hose bib adapter
- Make sure you have a strainer on the pump intake; else you'll fill your sprinkler/drip etc with grit.
- You may need a short piece of flexible hose from the pump to the plastic pipe for ease of connection, vibration etc.

Here is a good reference:
Elevation Pressure Loss

Rainbird, Hunter, and Toro all have good tutorials in their master catalogs(I get them at John Deere Landscape or similar irrigation store; HD and Lowes don't have them)

 

[turnkey4099]

Totally too small of hose, with unknown but probably poor friction coefficient. So you have huge friction loss.

Second, you lose at least 15psi just from head pressure(0.433/ft of elevation).

In this case, consider:
- Run plastic pipe from the pump to your distribution point. I would not go smaller than 1"; I would start with 1-1/4". It is cheap in 20' sticks at John Deer Landscape, Home Depot etc.
- On the end, put a hose bib adapter
- Make sure you have a strainer on the pump intake; else you'll fill your sprinkler/drip etc with grit.
- You may need a short piece of flexible hose from the pump to the plastic pipe for ease of connection, vibration etc.

Here is a good reference:
Elevation Pressure Loss

Rainbird, Hunter, and Toro all have good tutorials in their master catalogs(I get them at John Deere Landscape or similar irrigation store; HD and Lowes don't have them)

To run an impulse sprinkler well usually needs about 30psi. If you set your pressure switch to 40/60 it will be in the ballpark. As others have said, no matter what you do to the pump, you won't get useable pressure until you replace that linewith a far larger one.

Harry K