Congratulations on your new vessel. And, welcome to Trawler Forum.
It is often a good idea to verify that all faucets are completely shut off. For me that generally means I've left the cockpit shower spigot Almost closed. A partially opened faucet can mess things up.
Another thing to verify is your hose clamps. Boats vibrate and clamps can loosen, thus letting air into your system. Tighten the hose clamps.
I will leave more in depth troubleshooting to the experts. Good luck though, and welcome.