Just in case someone reads this through a search. I was able to resolve the issue.

I believe the popping noise was due to a partially clogged hot water vent pipe. It would build up pressure and then make a loud popping noise. If you remove the water jug and the jug plate. You will see a small aluminum pipe coming out of the left side. This goes down to the hot water storage tank. The manual states you can clean the water cooler with either vinegar or citric acid. I opted for citric acid at 16 oz per gallon. I made sure to pour some of the solution down the vent pipe. i then blew out the vent pipe and used a pipe cleaner to clean it. The problem hasn't came back since.