After speaking with another Rinnai customer service agent that was able to properly help diagnose the issue, he sent us the correct replacement parts. The first part that was replaced was the copper heat exchange unit. That was the main issue that was causing water to run inside the unit. The second was the three different O rings for the copper lines that run down from the heat exchange unit and plug into the valves. The last part that was replaced was the ventilation with a 2 in 90 cap to prevent rain from pouring into then unit. What I noticed after removing the tape is that the reason for it is that the previous installer should have raised the tankless appropriately 2 inches higher in order for the vent to be properly stubbed outside. I was at least able to still install the new vent as best as I could. But raising the tankless was not included in the contract, an estimate can be given if the owner would like us to raise it. After reinstalling the unit I turned the unit back on t