So I accidentally punctured one of the lawn sprinkler heads with a manual aerator because of overgrowth (& carelessness). Having replaced the pop-up pipe and head, I now have a problem I've never had before with any sprinkler system.

When this zone gets activated, the head pops up, but no water comes out (all other sprinklers in this zone are fine). It doesn't matter if the head is open all the way or closed all the way. I cleaned out the pipe, running it for a while with the head completely off, and I tried different heads just to see if it was a bad one.

Here's the weird part. If I press down on the head hard enough (while it's running), the water sprays just fine under my foot. But when I let go, the water stops completely. This leads me to believe that it isn't a leak somewhere, but I can't for life of me figure out what's going on. Thanks for any help anyone can provide.