My question to you is, what kind of glue did he use on CPVC piping. If he used wrong glue that might be the cluprit.

Click on: Cement Products - FAQ
For the information you desire. This will take you through the different types of cements and primers. Regards, Tom

CPVC requires CPVC solvent glue or one marked All purpose including CPVC. Since you mentioned culprit, we will assume something wrong happened. Yes?