# Air line tapped into roof drain



## 422 plumber (Jul 31, 2008)

I am using my K-500 to clean some roof drains in Chicago. Hat tip to Ron the Sewer Rat, for some very helpful advice. We popped a drain and we heard a gulping like noise, and we could see water splashing at the 90, about 10" down. We didn't have enough hose to run it directly into the drain, but kept filling and dumping 5 gallon buckets, all the water would drain, and I got about 35 foot of 1-1/4" cable down, so I was actually under the slab. I go inside and try to spin the brass cleanout plug off, no go. So I get the hammer and chisel, I break the cover and a hiss of air rushes out. I about crapped! It kept on hissing, and never stopped. I looked and discovered a 3/4" galvanized line coming over from the paint booth is tapped into the roof drain, right below the double wye. WTF!? The plant maintenance boss has no idea what it is, we don't know if it's condensate or a pressure relief drop or what. I am going back there tomorrow, so I hope to be able to solve this mystery. The nice thing about this plant, is that it's close to Midway Airport. When I'm upon the roof, I get to watch the jets taking off and landing.


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## ILPlumber (Jun 17, 2008)

A lot of factory maintenence guys tie the air compressor, air dryer, or holding tank solenoid automatic blow down valves into plumbing stacks.


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## Redwood (Sep 8, 2008)

ILPlumber said:


> A lot of factory maintenence guys tie the air compressor, air dryer, or holding tank solenoid automatic blow down valves into plumbing stacks.


Yep more than likely thats what it is...
However, that water will have oil from the compressor in it so it needs treatment before going in a drain and it would go to a sanitary drain not a storm drain...:whistling2:

Here we have to get a discharge permit for draining the water after treatment from the DEP.


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## Airgap (Dec 18, 2008)

If it's a compressor auto drain it shouldn't stay on all the time. Unless it's malfunctioning.


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