water exchanger unit AXHE-heating capacity:6.5kw,8.5kw,12kw, 18kw, 21kw, ... : 5/8INCH 3/8inch,1/2inch,7/8inchwater connection 50mmmain unit need dimensions: 400/335/530mmAxen is specialized in manufacturing different ... heat exchanger, etc. High efficient air to water heat exchanger unit