Water not flowing through new bathtub valve

I replaced the valve stems on our bathtub (Danco 3S-9H/C is the specific part). The cold water works correctly, but when I turn on the hot water nothing comes out of the spout. When I pulled out the valve stem to see what was wrong, a small trickle of water came out of the faucet, so I don’t think the pipe itself is clogged, but when the valve is properly in place nothing goes through it.

The valve is new and doesn’t have any sort of clog that I can see when I remove it. I’ve tried removing and reseating the valve stem, and also the seat and spring, but there’s still no water coming out.