# Water Hammer / Air in the pipes



## Dolby (Sep 18, 2018)

Hi,

Hoping you can assist.

I have a tiny garden that I hardly went in for many many years. This basically turned into a sandpit with a few dead plants 

I recently decided to change this and I'm actually really enjoying attempting gardening. One thing I did was get someone to install irrigation for me.

Now, when the system starts it makes an awful loud clank/clunk noise which - after Google - is probably air in the pipes. But here's the part I don't get :

*It does it the first time used every morning - not subsequent times!
*Surely air in the pipes is a one off issue - when it's running, where is the air?
*It only does it with the irrigation start - nothing else causes it

Any advice welcome ... Thanks


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## kaptain_zero (Jun 2, 2018)

Water can leak slowly out one or more of the sprinkler heads after it is turned off. It may take many hours to drain enough to cause the problem so that you don't have a problem during the day, but when it sits unused overnight, it has a chance to drain and allow air to enter the system. In the morning, during the first use, the air is forced back out and the water takes it's place.

I don't know much about how a sprinkler system is supposed to be installed as with close to 7 months of frozen ground around here... there's not much point in having water in pipes above the frost line which is about 5 feet down. It is done some places, but it seems like just after you turn on the water in the spring, it would be time to blow all the pipes dry so they don't freeze....

If I were to guess.... and I'm really guessing here, the underground pipes need to be fairly level to avoid this. If one is going down hill.... there is nothing in the pipe to prevent water going out and air getting in when not pressurized. Either that, or perhaps there is a slow leak somewhere, causing the same issue?


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## unclebucks06 (Apr 25, 2018)

Im going to guess pipe size is to small.


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