"rb" wrote in message ...
Need review of what horsepower does on pumps.

I have a well, 29' below where the pump will be. It now has a 2hp
Sta-Rite pump on it.

I'd like to put a 1.5hp Sta-Rite on it, because of economics.

Does the HP of the pump relate to how much suction it has, or does it
relate to the number of sprinkler heads I feed with it?

If it relates to number of heads I feed with it, I know I can get by with
a smaller number of pump HP. I have 3 sections of 4 heads ea.

Summarizing everything that's been said, you can't tell from what you've
presented. For example, what is the flow rating of the heads you are using?
Do you plan on expanding the system in the future? Does your system use a
pressure tank, (high pressure, low volume pump), or no pressure tank (high
volume, low pressure, continuous run pump)? From your description it may
even be that the smaller pump is preferable, if the larger one is oversize
for the application -- more likely to heat up because there isn't enough
water being pumped.

We recently had to fix a system that had a mismatch between pump size and
application - the original DIY'er had put in a large pump (future planning)
but a small pressure tank. Worse, the pump was high volume, low pressure,
not matched to the pressure tank. If you could stop the pressure switch
from chattering, it would fill the tank in seconds, then shut down while the
tank bled down during irrigation, but restarting after only a minute or two
of operation. We fixed it by replacing the original pump with a high
pressure low volume pump and replacing the small pressure tank with a 100
gallon hydro-tank. Now the pump runs for 3-4 minutes, then shuts down for
about half an hour. We also could have removed the pressure tank and
operated the irrigation system directly from the original pump, but there
was an outdoor sink at the green house that we didn't want to have to
replumb.

In your case, I'd take the information on my system to a local irrigation
systems supplier and get their advice. You'll probably find that they can
steer you in the right direction, avoid buying the wrong items - and that
their products are as inexpensive and probably better quality than what's
available at the box stores.