"Do not equate water pressure with air pressure. If you go with 50
may end up blowing your sprinkler heads into orbit, and or melting your
sprinkler components. Compressed air gets hot.
You can't use a typical 120v air compressor (6 - 10 cfm) and make up
the low airflow by increasing the pressure. "
The sprinkler system works with over 50PSI water pressure, but 50PSI
air pressure is going to blow it up? Or melt them? Now that is really
hysterical! Sure, air gets hot when it's compressed, which is why the
compressor gets hot. But when air expands, which is what it'd doing
when it leaves the compressor and goes into the sprinkler system, it
gets cold. That's how an air conditioner works.
I've blown mine out for 8 years with a 6 CFM Sears unit with maybe an 8
gallon tank. I let the pressure build to about 60 lbs, then turn on
one zone. Let it run for a couple mins, then turn off the zone, let
the pressure build back up, then do the next zone. Go through this
process twice for each zone. It's not as fast as using a high CFM
compressor, but it has worked well for me and saved me $500 so far!
Also, if you google, you'll find another recent thread on the same