[phreshout]

I recently moved into a house that has a lawn sprinkler system on a cased 40 ft well. I know I must blow out the sprinkler lines, to winterize. Pump is submerged, no pressure tank, but produces about 60 lb psi on demand.
1. How much air psi to blow through lines?
2. Is my 3 hp 20 gal compressor adequate enough?
3. At the well head, there is no shut off valve to the submerged pump, but there is a tee with a shutoff, so I can run a garden hose. I can also hook up air here. The shutoff is in the tee. Apparently, if I apply air at this tee fitting, psi would travel down to the pump (& check valve?), as well as the other way through the sprinkler heads. I would think this would hurt the check valve, assuming there is one, or pressurize the well? Is this not a good thing? Thanks, Rob