Guide for installing HydroFlow in combi-boiler One of the most widely used independent heating equipment is combi-boilers in small residential units without need of central mechanical room. Hard water in Iran, especially in the provinces of Qom, Mazandaran, Gilan, etc., causes the formation of limescale in the plate exchangers and scaling up the pump and internal equipment. Hard water at 60 to 65 degrees Celsius releases the highest amount of limescale (carbonate) that causes scale accumulation inside the plate exchangers or on electric elements (low heat transfer and low hot water temperature, water pressure drop are the signs of system blockage). The more the combi boiler works to heat up the water, the more energy it lost. The HydroFlow descaler HS-38 is the best way to control limescale and hard water problems. The HS38 stops scale build up and also remove the old existing scale in the plate exchangers , electric water heater , all hot and cold domestic water pipes, fixture units and faucets, washing machines and also the dishwasher. The HS-38 is very small, lightweight and easy to install, with a power consumption of 1.2 watts. By equipping the combi-boilers with HS38, it does not require polyphosphate water softeners which could be individually installed on each equipment.