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:
It looks like this is what you have:
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.
Another suggestion would be a variable speed motor controller. That would let you run only a couple sprinklers if that's all you need for an odd corner of the yard. Set it up to run whatever psi you want. Lower psi is cheaper to run by the way.
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.
Have something to add? Share your thoughts — no account required.
Ask the community — no account required