VITODENS 200 WB2A - Heatingspares247.com

3 Installation RequirementsFigure 3/C: Typical System Design (System Boiler - 4 Pipes)Note: The boiler incorporates an internal bypass to ensure adequate water flow, however one radiator(preferably in the bathroom) should be permanently open (fitted with two lockshield valves) to dissipate anyexcess heat. The System boiler system is illustrated below.• As shown above the system boiler utilises the DHW flow and return connections making theDHW fully controllable.• The following Viessmann control configurations are available:-Constant temperature = Compatible (Timed Control of DHW not Available)Timer with Constant temperature = CompatibleWeather Compensated controls = CompatibleUTD = CompatibleThe boiler will require a permanent live feed via plug 40. (See section 4.10)• The Viessmann DHW sensor MUST BE ATTACHED to the cylinder by secure means toensure good contact is made with the cylinder itself (as shown).• The DHW will always take priority over the Central Heating when timed demand is selected.• Where an unvented hot water cylinder is used the safety thermostat connected to thecylinder which controls the 2-port valve can be operated by a remote timer or via an internalH1 or H2, or external H1 Viessmann accessory.15