Logano plus SB315, SB615, SB745 - Buderus

7 DHW heating7 DHW heating7.1 Systems for DHW heatingThe Logano plus SB315, SB615 and SB745 floorstanding condensing boilers can also be used for DHWheating. DHW cylinders matched to these boilers areavailable as horizontal or vertical versions in different sizeswith 135 l tp 6000 l capacity. Subject to application, theyare equipped with an internal indirect coil or external heatexchanger.Primary store systems are ideal for DHW heating incombination with a floor standing condensing boiler. TheBuderus range includes the Logalux LAP primary storesystems (positioned on the cylinder) and Logalux LSP(standing next to the cylinder) in many output sizes.If the external DHW heat exchanger is sized correctly withlow return temperatures, high levels of efficiency can beachieved. A design return temperature of no more than40 °C is recommended ( fig. 33).AW60 °C60 °CBT 3516FWSKR PS1 70 °CVKFSMFSUPS22RK2RK11EK10 °C30 °C36 720 642 881-28.1ilFig. 33Primary store system for DHW heating with high efficiency at a low return temperature1 DHW cylinder for external heat exchanger2 External DHW heat exchanger3 Floor standing condensing boiler with Logamatic 4321and FM445AW DHW outletEK Cold water inletFSM DHW temperature sensor, cylinder middleFSU DHW temperature sensor, cylinder bottomFWS DHW temperature sensor, heat exchanger, secondary sideKR Check valvePS1 Cylinder primary pump (primary circuit pump)PS2 Cylinder primary pump (secondary circuit pump)RK1 Return for low temperature heating circuitsRK2 Return for high temperature heating circuitsVK Flow7.2 DHW temperature controlThe DHW temperature is set and regulated either bymeans of a module inside the Logamatic 4000 controlunit (e.g. FM445 function module for primary storesystems) or via a separate control unit dedicated to DHWheating.More detailed information on this can be found in thetechnical guides “Sizing and selecting DHW cylinders”and “Logamatic 4000 modular control system”.48Technical guide Floor standing gas/oil condensing boilers Logano plus SB315, SB615, SB745 – 6 720 802 589 (2012/01)