Logano plus SB315, SB615, SB745 - Buderus

5 Regulations and operating conditions5.7.4 Requirements of the fill and top-up waterTo protect boilers against limescale damage over theirentire service life and to ensure trouble-free operation, thetotal amount of limescale-forming substances in the filland top-up water in heating systems must be restricted.For this reason, the fill and top-up water has to meetcertain requirements depending on the total boiler outputand the resulting water volume of a heating system( tab. 16).The permissible amount of water based on the fill waterquality can be determined simply with the aid of thegraphs in fig. 31, page 43, and fig. 32, page 44, or with acalculation method to determine the permissible amountsof fill and top-up water ( chapter 5.7.7, page 45).Total boiler outputRequirements regarding water hardness and the amount of fill and top-up water V max[kW]Q ≤ 5050 ≤ Q ≤ 600Q > 600V max : no requirementsV max : calculate according to graphs in fig. 31, page 43 and fig. 32, page 44, as well asformula 3, page 45Water treatment is generally requiredindependent of output For systems with very large water content (> 50 l/kW), water should generally be treated.Table 16 Requirements for fill and top-up water for boilers made from ferrous material42Technical guide Floor standing gas/oil condensing boilers Logano plus SB315, SB615, SB745 – 6 720 802 589 (2012/01)