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wrote:
I just bought a house with a pretty sophisticated looking irrigation
system (Toro). I have no previous experience with these. The previous
owner purchased an annual maintenance service to start it up in the
spring and winterize it in the fall. The guy came out today --
terrific fellow -- to purge the system. He told me it was $285 for the
annual service. I am not sure I want to pay that, and I KNOW my wife
will flip out when she hears, but I don't want to just let such a nice
system go unused. I do have access to an air compressor for purging,
but don't know trying to self-service all this myself is over my head.
Anyone have any advice or know where I can get detailed instructions
about how to do it myself?

I had a system put in about 10 years ago and have done all the
maintenance myself. At your rates, that would be about $2,800 saved.
I use an old Sears compressor, 10gal maybe, 6.4cfm at 40psi to blow it
out. I attached a gate valve and male air fitting to the water line.
I let the compressor get up to about 80psi, then turn on the zone for
about 3 mins. The pressure drops down to about 40 or so. I go through
all the zones twice and make sure only some mist is still coming out.

Other than that, I've spent maybe $100 for sprinkler heads, which are
easy to replace. A lot depends on your repair skills.

One other thing I would recommend, particularly if you are paying for
water. Do a flow rate test on all the heads, using a 5 gal pail or
similar to catch the water for a timed period. Then you will know the
actual gal/min from each head, which can be different depending on the
size of nozzle, which is frequently changable. Factor in the degrees
of coverage. For example if one nozzle is putting out 1gal/min and
doing 360, while another is putting out 1gal/min in 90deg, then the
latter area is getting 4 times as much water, or an effective rate of
4gal/min. You can also factor in the throw distance if there is a
significant variance, to figure out the relative rates for each head.
You want them normalized. So, in the above example, the 90 deg area
head should have a nozzle putting out 1/4 the rate of the 360 deg one.
That way you will have even water distribution. If you don't you will
be wasting a lot of water on some areas in order to give other areas
the right amount. You can also do this measurement with tuna cans
which will show the effects of overlap from multiple heads hitting a
particular area.