Yellow cap inside the vent stack

[Sam Morris]

Does anyone know what this yellow plug is and why it would be inside the plumbing vent stack ? 349123491334914

[Jerry Peck]

Plumber's vent test ball.

Plumber's forget and leave them in place frequently.

Completely blocks the vent.

Plumber needs to attach its chain to it (to keep it from falling down into the vent), deflate it, and remove it.

[Gunnar Alquist]

Plumber needs to attach its chain to it (to keep it from falling down into the vent), deflate it, and remove it.

I am going to disagree here. Plumber needs to verify that this is indeed a vent pipe that is connected to the plumbing system BEFORE removing the ball. I have seen a couple of pipes that were not actually connected to the plumbing DWV system, and if the cap is removed, leave a nicely plumbed hole in the roof.

[Jerry Peck]

I've never seen a vent or other such pipe capped with a "cap" inside the pipe like that.

All caps I've seen fit over the pipe.

I've seen "test" caps which did fit into to ID of the pipe with a recessed area, but they also had a flange which fit against the end of the pipe, the part "in" the pipe was glued in with PVC cement. When the test was done and the water drained out of the pipe, the end at the pipe with the test cap was cut off. The test caps were always on test tees or a horizontal pipe from a sanitary tee or wye & 1/8 bend (so the vertical stack could be filled with water for the DWV test.

I'm not saying that is not a cap, only that I've never seen a cap inside like that. Keeping in mind that I'm also not claiming to have seen everything - because I haven't.

[Dom D'Agostino]

The newer ones all mostly expanding gasket type caps (https://www.lowes.com/pd/Oatey-PVC-Test-Plug-Fitting/3880609?cm_mmc=shp-_-c-_-prd-_-plb-_-google-_-lia-_-142-_-indoordrainage-_-3880609-_-0&placeholder=null&ds_rl=1286981&gclid=EAIaIQobChMI0ciox77e7gIVhvDACh39_QAQEAQYBCAB EgLsNPD_BwE&gclsrc=aw.ds).
Have a flange that prevents dropping inside the pipe.

The OP's picture looks like this one.

https://www.ferguson.com/product/cherne-gripper-1-12-in-dwv-systems-and-sewer-plug-c270210/_/R-41869

[Gunnar Alquist]

[QUOTE=Jerry Peck;287563]I've never seen a vent or other such pipe capped with a "cap" inside the pipe like that. All caps I've seen fit over the pipe./QUOTE]

Jerry,

Fair enough, I am referring to having seen caps (over the pipe) of one type or another (plastic or rubber) rather than a test ball, where the pipe was not connected.

But, my point is that people (homeowners or tradesmen) do crazy things and if the pipe is not connected, the HI could be liable for damage caused by the removal of the thing that was keeping the rain out.

[Jerry Peck]

Dom,

The photo does look like that one you linked to.

Gunnar,

i agree with what you are saying, and my say "Plumber needs to" puts that responsibility on the person it should be on - the plumber.

And if the HI is one of those who 'fixes things' during their inspection ... then, yes, it is on them ... and maybe then they will finally grasp why the home "inspector" should not be playing the dual role as home "repairmen". They get no sympathy from me for their misdeeds and errors or having to pay for such as they shouldn't be doing both.