Thank you for reaching out with your concern regarding the Epson XP-15000 printer. I understand the frustration when your printer is not recognizing the installed cartridges after waterproofing. Let's address the issue based on two possible scenarios you might be facing:

1. If You Installed Chipless Firmware: It appears that your printer may have undergone an automatic firmware update, which unfortunately erased the chipless firmware. This feature is widespread across various platforms, including the printer itself and any connected computers, leading to unexpected updates. If a visitor used your printer with their computer and had auto-updates enabled, it could have triggered this. The good news is, when you initially installed the chipless firmware, the provider should have supplied you with a recovery code. Please contact the seller for guidance on using this code to restore your printer's functionality without the need to repurchase the firmware. Here is an article about how to disable Epson's automatic firmware update:https://bchtechnologies.com/blog/how-to-disable-an-epson-printers-automatic-updates/
2. If You Haven't Installed Chipless Firmware: The issue might stem from modifications made during waterproofing, such as relocating the CSIC board, which prevents the printer from recognizing the cartridges. The printer relies on the CSIC board for cartridge detection, and any changes in its placement can disrupt this function. To resolve this, you may need to consider converting your printer to a chipless model before undertaking modifications like waterproofing. Here is a video showing how to waterproof your XP-15000, which mentioned that you need to relocate the CSIC board, and also install the chipless firmware before doing the waterproofing:

Furthermore, we invite you to visit our YouTube channel, BCH Technologies, for a wealth of information on refill tips and printer repair instructions that might be beneficial in this situation and for future reference. You can find us at BCH Technologies or directly via this link: https://youtube.com/@bchtechnologies. We constantly update our channel with helpful content to assist our customers in maintaining optimal printer performance.

We appreciate your support and patience as we work through this issue together. If you require further assistance or have additional questions, please do not hesitate to contact us.

Thank you once again for choosing BCH Technologies as your go-to source for printer solutions.