Today I performed a diagnostic on the Verna tankless water heater, which was displaying error code 79. Upon inspection, I found that conversation is dripping into the unit, causing the error. This is the same issue we were previously called out for, and the customer is aware of the recurring problem. At this time, the unit is functioning, but continues to experience internal conversation issues that can lead to future failures. Due to the age and ongoing condition of the system, I will be leaving estimates for a full replacement of the tankless water heater for the customer to review. All findings were discussed with the customer prior to departure .