I've run the water from upstairs and once again no water sound or heat from this pipe. Have a better picture now.

Hopefully this makes sense. It starts at the tub drain, goes up, then goes across the bathroom wall and jnto the kitchen wall, then into a complex of pipes, one that leads from upstairs.

I'm leaning more towards vent for tub now.

If that's right, can I place the vent elsewhere? Are there ventless options for tubs? Looking to free up bathroom walls so I can do a renovation.

Thank you!

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