On Sun, 16 Feb 2020 05:17:31 -0800 (PST), 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.


Shallow well pumps struggle to get 60 PSI and that is well below the
range of city water that is usually 80-100. When the pump reaches max
pressure it just cavitates. As long as there is still water flow, no
harm. The only problem is when it is not making the switch and water
is not flowing. Then it will over heat. PVC pipe will melt and you
could even damage the seals. I agree all pumps will give you the flow
at any given head pressure.