kn series gas boiler installation & operating ... - Agencespl.com

Page 14KN INSTALLATION AND OPERATION INSTRUCTIONSBoiler Piping ConnectionsThe supply and return connections should be sized tosuit the system, see Table 8.Table 8 - Supply & Return Pipe SizingModel Supply ReturnSize Size Size600 2" NPT 2" NPT1000 3" NPT 3" NPT2000 3" NPT 3" NPTPump RequirementsThis boiler requires a continuous minimum water flowfor proper operation. The system pump must be sizedto overcome the head loss of the boiler and the heatingsystem in order to achieve the required temperature rise.If the system contains hydronic antifreeze this must beconsidered when sizing the pump. The temperature riseacross the boiler must never exceed 100°F, 55.6°C.Low Water CutoffEach KN boiler comes equipped with a factory installedlow water cutoff.Expansion Tank & Air SeparatorAn expansion tank or other means to control thermalexpansion must be installed in the heating system. Anexpansion tank must be installed close to the boiler onthe suction side of the pump. An air scoop andautomatic air vent must also be installed to eliminate airtrapped in the system.Primary/Secondary PipingFigure 9 shows a typical primary/secondary pipingsystem. A dedicated pump is used to maintain aconstant water flow through the boiler. Systems usingmultiple boilers can be installed using a primary/secondary manifold system, Figure 10.Reverse Return PipingSystems using multiple boilers can also be installedusing a reverse return system, Figure 11.Piping For Use With Cooling UnitsThe boiler, when used in connection with a refrigerationsystem, must be installed so the chilled medium is pipedin parallel with the boiler. Appropriate valves must beused to prevent the chilled water from entering theboiler.When a boiler is connected to a heating coil that maybe exposed to refrigerated air from an air handlingdevice, the piping system must be equipped with flowcontrolvalves or some other automatic means ofpreventing gravity circulation of the boiler water duringthe cooling cycle.NOTE: Minimum boiler flow rate is 15 gpm.Maximum boiler flow rate is 150 gpm.Figure 9 - Typical Single Boiler Primary/Secondary PipingNOTE: Not all system valves maybe shown. Consult local codes foradditional system componentswhich may be necessary.