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Active Member


Saturday, September 10th 2011, 7:43am

System Startup Pressure Testing

I have a fairly large system I'm about in the middle of installing. It has over 2500 feet of poly pipe and about 150 heads with 12 zones. My yard is approximately 1 acre. I trenched the whole system rather than using a knife for various reasons I won't get into. Now I'm wondering when I can safely backfill....

I'm wondering how, and if anyone pressure tests their system before firing it up.

I can see pressure testing the main line up to each manifold. This is fairly easy since the main can be turned on, one valve on each manifold can be opened to allow water to reach the manifold, then closed and the connections inspected. After that it gets a little more complicated. You need water at operating pressure at each connection to test it properly, and if it's tested with heads in place one would get pretty wet. If each head is removed and capped, it would be very tedius, and some type of valve would have to be put at each location, in my case about 150 to release water until it reached that head, then pressurize to operating pressure.

Last, I have automatic drains incorporated into the design. They essentially create a leak so to speak. Not under pressure, but when the pressure is released. If they are going to slowly drain the line over time anyway, does a small drip leak in a zone really matter?

I'm looking for the smartest and best way to do this if it's even done at all.


Central Irrigation

Supreme Member

Posts: 371

Location: Central Minnesota


Saturday, September 10th 2011, 8:39am

Pressure test the mainline only. I hope you've installed some sort of backflow prevention decvice!? These devices have a test cock on them that allow you to insert a pressure gauge in order to test the device. These test cocks work great for pressure testing the mainline. Fill the mainline until you're confident it is fully pressurized then turn off the water to the system. If the pressure gauge drops, you have a leak in the main. If it holds steady pressure, you're in business.

Like you stated, a leak in a zone line isn't as crucial since you have drains. It still isn't preferred, however, but I wouldn't go and cap all the heads in order to be absolutely certain. If a leak of decent size is present, it will show up over time.

Install all valves before pressure testing the main.

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