Jacuzzi bubbler inop

Factual Questions
1

I have a very old jacuzzi about 25 years old. From what I can tell the anti siphon or check valve seems to be stuck shut for the air bubbler. I can’t find anyway to access it without ripping off the sides and some insulation. I am wondering if charging the input line with my hose might put too much pressure on the plastic lines and do some damage if it does not brake loose. I ran a wire up about 4 ft before it hit anything solid.