pressure test failed

[Dan Simoes]

I picked up a 3" quick cap and mounted a valve in it.  I put 14 psi
through it and was unable to keep the cap on the intake hose.
This tells me that I need to mount the cap inside the hose (will try
something like Brett's tupperware) or my system is so tight that the air
is just coming right back out the intake.  Likely the former.

I also picked up a 3" white PVC plug thinking that would fit in the
intake hose.  It's just a bit too large.  Something 2 7/8" would
probably work fine.