Dwv pressure testing


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Old 06-26-20, 06:48 PM
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Dwv pressure testing

so I finally got around to testing my dwv system.
im hoping to do a rough in inspection with the town in the next week or so.
anyway, I was going the water testing route.
i plugged all the drains and the toilet. Went up to the roof with the hose and started filling the system with water. The system is pvc
for the most part things seemed ok, but the water level did sink over time.
I went down and inspected everything, but didnít see any leaky joints.
I was thinking some air will exit the system, and as it bubbles up it would reduce the water level, but how long does one wait and how much air can one expect to escape the system.
i can see why the air testing method might be preferred, but am Leary with the pvc.

 
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Old 06-26-20, 08:24 PM
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The air test method can be used for DWV testing but the water method is recommended.
Is your line tied into the sewer ? If yes.... how did you seal it ?
Sounds like something isn't sealed completely.

The inspector is going to get there and expect to find the pipe full.
Any air in the system would be worked out pretty quickly.
 
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Old 06-26-20, 09:16 PM
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Thanks for the reply.
its on septic, but same should apply.
im using a cherne 3Ē test ball plug just above my lowest clean-outhttps://www.oatey.com/products/cherne-singlesize-plumbing-testball-plugs-1709245421
it seems to have a pretty good seal as I never see any visual leak around it once Iíve inflated it.
i will rerun the test tomorrow and cross my fingers
 
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Old 06-27-20, 09:32 AM
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I retried this morning, although instead of sealing all the outlets at the beginning, I went a different route.
I started with the main 3Ē plug above my lowest cleanout.
then I started filling the system with the drains open.
the lowest drain spots were the toilet and the shower drains. The toilet has a 3Ē pipe below it that joins the main stack about 28Ē below the floor level. The shower has a 2Ē drain that travels about 12Ē down before hitting its p- trap.
so I started filling, watching the water level rise in those two drains. When it got to the top I sealed those pipes off so there wasnít any air trapped inside.
from there I filled the system more. At this point it was mainly the sinks that were left, so I filled until water started coming out and then I plugged each one this probably made less differences because of the venting.
The only pocket of air would be in the laundry drains, which is covered automatically in the box, until I rip that closure out.

this process seemed to make a big difference as the water level at the roof was nearly the same after 15 minutes.
 
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Old 06-27-20, 10:21 AM
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Putting the seals in wet probably made for a better seal too.
Sounds like your system is in pretty good shape.
 
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Old 09-07-20, 05:33 AM
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Quick addendum:
had my test a week or so ago.
sort of a disaster.
its been a little while since I was doing my initial tests on dwv, during that time Iíve been using the system.
come the day of the test and Iím filling up the system with water.
I get all the way to the roof vent and then, whoosh, the water floods out.
first time into the basement where the main stopper failed.
second, third and fourth times at the shower. Also, I have a shower pan, not a bathtub, so water fills that, and then floods into the room, and then down into the basement.

basically what I figured out is that I should have cleaned the film off the inner part of the pipe where the plugs were holding back water. Once the pressure got to a certain level they would slide out and flood me out.

so if youíve been using you drain system, make sure you clean the top couple inches of the slippery film that developed, so your plugs donít slip out on you.
 
 

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