Customer called John the plumber out today because he’s experiencing an error code on his gas, tankless water heater located outside. error code reads 33. When technician arrived, customer informed him that the error code is no longer showing and a tankless water heaters are working. With technicians experience, he knows error code means that the heat exchanger needs to be replaced. But without seeing any error codes, technician cannot 100% be sure of the problem. But technician did notice that the water heater is from 2017 and it’s hooked up to a recirculating pump. Having a recirculating pump on a gas tankless can shorten the life span of the unit due the water in the unit constantly running. Due to the age of the unit technician recommends that customer gets it replaced.