Hi. I played your map last night and there are a couple of issues, but I think you should address the scale of the map first.
First of all, it's so large the game stops rendering it entirely. This is an issue. Large maps can be fun in TF2 but are usually broken up into several stages like dustbowl. This map needs to be shrunk. When we played it last night I don't think we completed a round because of how large it was players were getting lost and just exploring rather than playing the game.
Your vents are also maze-like unlike turbines. The vents in turbine are simple and easy to understand and orient yourself if you get lost. Your vents are a bit too much for what you're going for.
Also notice again how the map is so large the game is just refusing to render it. I really think you should look at your scaling of the map and cut it back a fair bit.