Blow out vs gravity drain


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Old 10-14-12, 08:10 AM
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Blow out vs gravity drain

I have a smaller 5 gallon 3hp air compressor. I would like to blow out the sprinkling system and install gravity self drains in the lowest distant areas. After blowing out the system the and blowing air through the zone a second and third time, there is not enough pressure to raise the sprinkler heads but I can hear air leaving the sytem. Hence I would like to install gravity drains also. Any problems?? Would the air pressure damage the self draining valves.
 
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Old 10-14-12, 09:22 AM
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Welcome to the forums! Your compressor probably won't have enough volume to pressurize the entire system until the heads pop up. Takes quite a bit. If you can hear air at the far end, you're good. You mention "self draining", what is that? You can install drains on the far end, but you will need to have them as manual valves and only open them when you clear the system for winter.
 
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Old 10-14-12, 09:50 AM
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Doesn't take a lot of pressure to blow out a sprinkler system, it's the volume of air it takes which is the problem for most home owners.
 
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Old 10-14-12, 10:44 AM
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You mention "self draining", what is that?
They make automatic self draining valves in both plastic and brass. They are normally open and close with about 3 psi pressure. The major hitch is that the piping for the entire system has to be laid so that it has a downward slope to the drain. I personally would want the drain in an accessible pit like a valve box.

1/2" Brass Drain Valve

Orbit Drain Valve 51241
 
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Old 10-14-12, 05:39 PM
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Gotcha, Furd. Curious, though, what if something got in the water system like a piece of trash, would it affect the draining/sealing properties? It's sort of like 4wd....I like to hear the gears grind rather than relying on an electrical relay. I'd prefer to have a hard drain at the end in a valve box, too.
 
 

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