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Repair low head drainage? Hammering. Spitting air.

MSidoti

New Member

Posts: 2

1

Wednesday, September 15th 2010, 9:26am

Repair low head drainage? Hammering. Spitting air.

Hi, Need some advice please.
Had a new 10 zone Rain Bird system installed 2 weeks ago and we're just starting to use it.
1st issue is hammering. 5-10 seconds of pipes hammering when the first 5-6 zones come on/off.
2nd issue is low head draining. Installer didn't seem overly concerned about it and said the property slope will result in the lower heads draining.

When the zones come on they spit air for a minute or so before full water flow.
Is that normal-shouldn't the lines be pressurized and full of water for the most part?
Are all these issues all related?
Should I replace all heads heads with those that have check valves if these do not.
Thanks for any help.

This post has been edited 2 times, last edit by "MSidoti" (Sep 15th 2010, 9:52am)

Wet_Boots

Supreme Member

Posts: 4,102

Location: Metro NYC

2

Wednesday, September 15th 2010, 11:12am

It's okay for sprinklers to spit air, even if it isn't aesthetically pleasing.

MSidoti

New Member

Posts: 2

3

Wednesday, September 15th 2010, 12:29pm

Thank you. Would you suggest to just let the lower lateral lines & heads drain and not worry about it? Would the fact that the lateral lines empty out contribute to the hammering? Thanks

Wet_Boots

Supreme Member

Posts: 4,102

Location: Metro NYC

4

Wednesday, September 15th 2010, 12:48pm

If there are banging noises when a zone is first opened, that is something other than water hammer. Eliminating head drainage might help. You have to try it to be sure.

Central Irrigation

Supreme Member

Posts: 364

Location: Central Minnesota

5

Wednesday, September 15th 2010, 5:16pm

That's why I install heads that come preassembled with check valves. It eliminates low head drainage and keeps all lines full of water (which greatly reduces the spitting of air you are referring to). Not to mention, it is a great water saving feature. Just think about all that water that just drains away! And if you're paying for it....WHOA!



Not sure what brand of head you have, but replacing the lowest head on the zone would help. Generally a head with a check valve will hold back the water up to 10-12 ft of vertical rise above the head.

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