I believe this is the vent to my plumbing but I’ve never seen a cap like this. Any ideas?
Use a flat piece of metal or wood and lay it across the cap, then turn. It will apply pressure to two of the nubs instead of one, preventing damage.
This worked like a charm thanks. Surprised how easy it ended up being. When I tried a different method it felt like it was glued shut.
Fantastic, glad it got you situated! Appreciate the update!
Put some ice and water in a plastic bag and sit it on top of the cap. Let it sit there long enough to cool down the cap.
While the bag is sitting on it, pour hot water on the ground against the pipe to heat up the pipe.
The cool cap will contract while the warm pipe expands. This might loosen it enough to use a straight bar to unscrew the cap.
Edit:
I’m guessing that the real tool would be something like this:
https://www.grainger.com/product/SUPERIOR-TOOL-Drain-Wrench-Rubber-45W758
I assume if it is a solid material, then the standing nubs are for using a spanner bar across them and turning. I haven’t seen this specific one before. Sometimes they are depressions and you have a pin spanner wrench.
It’s solid but not very strong. I tried to use a small wrench and it was breaking the nubs. The thing is incredibly tight
Wrench on one nub, or across two like a bar? Could be they have a tool that engages all 4 nubs at once so they don’t snap off, or thing was over tightened.
I’d get a spare bit of wood, press it against one of the nubs, and then smack it with a hammer repeatedly. If you’re careful it shouldn’t stress the nub too much but the vibration may unseize the thread.
Sewer cleanout probably. Never seen a cap like this before though, looks kinda flimsy. Maybe get a piece of plywood and cutout/drill for holes that align with the nubs and turn the plywood so you can put force on all four nubs?
These have a spring loaded flap in the center that lets out sewage if there’s a blockage downstream. Lets it out in the yard instead of your house.
As for opening, I use channel locks opened up all the way wide on two of the adjacent lugs and turn left.
Source: former sewer worker that would whipline these and televise.
Yes that’s exactly what it looked like when I pulled it out!
This is the one time I’ve seen a 3d printer might be more useful than using wood.
Flat blade screw driver and a hammer. Right tight left loose. Press the screw driver against the cap and tap it until it loosens
Take two pieces of wood, longer than the caps diameter. Drill a hole into one of them large enough for a screw. Put screw through and screw it into the other piece of wood, but leave enough space. Lay the contraption on the cap so that two opposing pins are between the woods. Turn screw tight so that the construction grabs those pins tight, like a vise. Turn anti-clockwise to open.
Do not step on it and call the authorities! LOL.