For instance, the corrosion issue of the heat exchanger in the acid cooling condensation have become a very importance problem for condensing gas water heater. There are 2 major solutions: 1) Apply a protection coating on surface of the Cu heat exchange tubes; 2) Make the heat exchange tubes by corrosion resistant material (such as stainless steel, Al alloys).

The recent years research shows that, the stainless-steel material is ideal for condensing gas water heater and wall-hung furnace heat exchanger. Stainless-steel could effectively prevent corrosion issue of the heat exchanger in the acid cooling condensation, and there is no need of coating onto the tubes.

But there are still some problems to be solved: 1) How to choose brazing material? It should be corrosion free to the acid cooling condensation, and could be brazed at compatibly low temperature, to avoid erosion; 2) Due to lower thermal conductivity of stainless-steel compare to copper or common steel, the design of the heat exchanger has to adapt and enhance the heat exchange feature, which end up with complex structure and thinner wall thickness, how to dispense the brazing paste effectively, stably and efficiently become an issue.

For condensing gas water heater and wall-hung furnace heat exchanger, Shanghai Xuanshuo could provide material choice and paste dispensing solution recommendation service.