Online auxiliary water heater

This HVAC schematic sample was drawn on the base of Wikimedia Commons file: Online Auxiliar Water Heater Diagram.svg. [commons.wikimedia.org/wiki/File:Online_Auxiliar_Water_Heater_Diagram.svg] This file is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license. [creativecommons.org/licenses/by-sa/3.0/deed.en] "A central heating system provides warmth to the whole interior of a building (or portion of a building) from one point to multiple rooms. When combined with other systems in order to control the building climate, the whole system may be an HVAC (heating, ventilation and air conditioning) system. ... A district heating system uses centrally located boilers or water heaters and circulates heat energy to individual customers by circulating hot water or steam. This has the advantage of a central highly efficient energy converter than can use the best available pollution controls, and that is professionally operated. The district heating system can use heat sources impractical to deploy to individual homes, such as heavy oil, wood byproducts, or (hypothetically) nuclear fission. The distribution network is more costly to build than for gas or electric heating, and so is only found in densely populated areas or compact communities." [Central heating. Wikipedia] The HVAC schematic example "Online auxiliary water heater" was designed using ConceptDraw DIAGRAM software extended with HVAC Plans solution from the Building Plans area of ConceptDraw Solution Park.