... , CCC,SGS2. Anti-freezen&pressurized3. With single or two coils in the water tank, also without coil in it4.5 years ... guaranteeWater tank (interior): SUS304-2B food grade ... heat tubeVacuum tube: 58mm diameter, 2100mm lengthworking station: controller, Circulation pump, expansion tank 5L-8L, manometer, flow-meter, pressure relief valve, ...