That was going to be my first response.. but its in the deep end. Not very centrally located for a booster pump. Maybe its a stub for some kind of water feature. ??Abandoned booster pump?
Probably the Pool Light Junction Box. Normally they are located at the equipment pad and are brass on older pools, but not always.
Yeah that's the issue, when I remove the cover and turn on the pump there is no suction or outward blowing pressure. Once the cover is removed it's just a threaded hole and I'm not sure where the plumbing goes. Here is what the cover looks like:Based on the pool photo and the plumbing photo, my guess would be a suction-side cleaner port. Normally they have a little spring loaded door that opens but maybe not in this case?
If you take the plug out, turn the pump on and feel suction there, that is what it is.
r.
When you turn the pump on, then move the valve to one side and see what happens, then move it to the other side and see what happens.