Ngoan Nguyen called us out several times to look at the same exact issue. Our company poliye is the FIRST estimate is free, any follow up estimates are an $85 service call charge. Ngoan Nguyen was billed for additional trips and refuses to pay stating " I thought it was a free estimate", yes the FIRST ONE WAS!! We were called out several times for the EXACT same issue and each time told them we recommend a new heater, same as everyone else told them according to Ngoan. Evidently our gas and time are not respected, I wonder if Ngoan works for free like Nogan Nguyen expects us to do!!!