The tankless water heater was working perfectly when we left, our technician ran the hot water after he completed the maintenance on the equipment, alongside the customer. Everything was working perfectly. He did not his a reset switch (as there is non). What we found was a breaker tripped inside the unit, which is an anomaly. It took two months for this invoice to be paid, (we didn't charge for the second visit) and secondly, we discounted the invoice to reflect a credit for the servicing of the tankless water heater as a courtesy. The customer eventually came into our office to pay, and after running around town to different (wrong) addresses, he was furious and agitated. Our computers were down due to a loss of power which fueled his frustration, but we eventually were able to process payment and get him on his way. We genuinely understand the situation with no hot water and how this effects our everyday lives, but this was no fault of our technician. As I stated before, and to the customer, he was there when we tested everything upon completion of the service and the heating and water heater were both working satisfactorily.