View Full Version : Thoughts on auto-drains

05-31-2007, 09:17 AM
Thoughts on auto-drains - main line, sprinkler lines, both, neither? Winterizing set up?

Anything else in general to do or avoid when installing a sprinkler system?


Gary Swart
05-31-2007, 09:09 PM
When I installed my underground system 24 years ago, I put them in all of the low spots. Problem is, I don't really know if they are working or not so every year I blow the lines with compressed air. Now that I have a good sized compressor, I can do it myself, but before that, I paid $50 a year to have it done. If I were doing it again, I'd save the few bucks they cost and buy a cold beer or four.

06-02-2007, 08:31 AM
Does anyone know of online instructions on how to blow out a system (Wilkins 720A)?

I, too, have a largish compressor (26 gal, 150 psi).

What pressure should I use? What fitting should I use to connect the compressor to the Wilkins?

How do I test that the breaker is working?

Gary Swart
06-02-2007, 09:06 AM
Pressure has little to do with blowing out a sprinkler system. It is the volume of air that does the job. With home sized compressors, you blow one zone at a time. I use two 60 gallon tanks of air to blow each zone in my system. The pro yard service companies use the big industrial compressors and can blow all zones at once and can do the job in a fraction of the time. How I do mine, and this may not be the only way, is to remove the backflow preventer which leaves me with half of a 1" copper union. I made an adapter with a ball valve to connect my air hose to that. To blow a zone, I manually open the zone's valve and then turn the air on. When the tank is empty, I turn the valve off until the tank has refilled, then repeat. I store the backflow preventer inside to to make sure it will be safe. The backflow preventer testing in my city must be done annually by a licensed inspector that I choose for a list provided by the city. They attach gauges to the petcocks, and I believe they use a small air pump to determine the unit is functioning. I haven't paid too much attention since it is not a DIY job. Perhaps you could find a shop that did testing and take it into them.