I touched it off it fell off (not properly secured) water under pressure came out. I shut the water off put it back in place turned the water on and water was flowing through it. I turned the hose bib next to it on and then off and the water stoped flowing through it. Is it some kind of pressure relief valve for the whole house?
What was on the other side of the wall, or on the next level right above it?
The living room is on the other side so drywall and nothing is above it untill the sofit.
Just say you don’t know what it is and recommend speaking with the owner or a further evaluation to determine its purpose.
Its bank owned so they will need a plumber.
Were the plumbing supply pipes PVC or CPVC?
main supply PVC