"Joe Bleau" wrote in message
...
The people who maintain my irrigation system always come around with a
super heavy duty diesel compressor they tow around behind a truck. I
believe it takes more air than ANY shop compressor can produce to blow
out an irrigation system. However, somwhere I recall having heard
that a system can be blown out by reversing an ordinary shop vac.
This sort of makes sense since it is a lot of volume that is required
rather than high pressure. Hope this helps.

I use a small compressor to blow out my water lines when I close my cottage
down for the winter. Works fine; water gushes right out. I can't picture a
shop vac doing much of anything; but haven't tried it.

I have a small HF compressor also. For light work it is okay, though it
will only power a small air hammer for a short while before you have to let
it catch its breath.
I tried using it at 35 degrees last week, which turned out to be serious
abuse, and survived.