Rainy day question....... The other day I saw what I think is an old atmospheric vacuum breaker located outside the house on the copper feed to a residential manifold. But I am not sure if it is a pressure vacuum breaker. It has no valve handles. Nor any ports of any kind, except the 3/4" input on the bottom and the 3/4" output on the side. The canopy was missing and you can see the plastic poppet inside. There is a single cast-in-place bar across the top where the canopy would go. A single post in the center of the white plastic poppet floated into the bar. Well, it didn't "float" and seat correctly when I turned on the water feed to it. I poked at the poppet until it seated, however it does seep some water. So, this is an AVB? Or a PVB? Did PVB's ever come without built-in valves or other ports (that I see on new ones) besides the inlet/outlet? What visual differences are there in AVB versus PVB?