On 2/16/20 7:17 AM, trader_4 wrote:
On Sunday, February 16, 2020 at 6:59:04 AM UTC-5, Dean Hoffman wrote:
On 2/16/20 4:59 AM, Jerry Salinsky wrote:
I am thinking of installing a 1 HP water pump to water my lawn. How many
sprinklers can it support? Is there a rule of thumb or some math to
calculate?

What would happen if I don't install enough spirnklers? I worry the
pressure in the pipe system would be high and ruin the pump.

The sprinkler is this type:

https://upload.wikimedia.org/wikiped...echanism_2.jpg

It looks like this is what you have:
https://www.rainbird.com/products/35a-series
There's a chart on the lower left corner that gives you pressure and
flow requirements. It looks like you need a minimum of 30 psi to run it.

And there is an output chart for the pump too. A big unstated here is where
is the water coming from? A 20 ft well, above ground tank, etc. Pipe size?
That sprinkler type is unusual for watering a lawn, typical is a pop up rotor
type, though you could use it. If it's a 1hp water with good supply of
water at ground level, it could probably support half a dozen of those.
With a typical water pump for such an application, it would be impossible
to get a dangerously high pressure, there is a max that it's incapable of
exceeding.

You might want some sort of pressure relief on the output of the
pump. The water lines to the sprinklers might be the weak point and be
damaged or blown apart if you don't have enough sprinklers. Of course,
the pressure relief point of the valve has to be low enough and the
flow capacity has to be high enough to get rid of the excess water from
the pump.