RBI SPECTRUM Series Installation & Operation Manual

Also see for SPECTRUM Series: Installation and operation instructions Installation and operation instructions

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SPECTRUM INSTALLATION AND OPERATING INSTRUCTIONS Page 13Variable Water FlowsFigure 5 shows a typical primary/secondary pipingsystem. A dedicated pump is used to maintain aconstant water flow through the boiler. This boiler pumpis sized to overcome the head loss of the boiler andnear piping while supplying the flow rate required tomaintain the desired temperature rise across the boilerheat exchanger. The system pump is sized to providethe required flow to the heating system. The boiler pipingconnections to the heating system piping must not bemore than 12 in, 305 mm apart to ensure zero pressuredrop, see Figure 5.Low Return Water TemperaturesTo prevent the problems associated with condensationof the products of combustion due to low return watertemperatures a primary/secondary piping system witha bypass and bypass valve must be installed, seeFigures 6 and 6A. The bypass and bypass valve mustbe sized the same as the secondary piping. A balancingvalve must also be installed in the supply side of thesecondary piping downstream of the bypass. Thebalancing valve should be adjusted to divert some ofthe heated discharge water into the return water untilthe required inlet water temperature is achieved. Theprimary and secondary pumps should be sized toprovide the required flow through each system. Theboiler piping connections to the heating system pipingmust not be more than 12 in, 305 mm apart to ensurezero pressure drop, see Figures 6 and 6A.Multiple Boiler SystemsSystems using multiple boilers can also be installedusing a primary/secondary manifold system, Figure 7.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 fl ow-control valves or some other automatic means ofpreventing gravity circulation of the boiler water duringthe cooling cycle.DOMESTIC WATER SUPPLY PIPINGCAUTION: Proper controls must be used to preventwater supplied for domestic use from exceeding130°F, 54°C or a scald injury will occur! When higherwater temperatures are required for appliances suchas a dishwasher, a mixing valve or some othertempering means must be installed. Households withsmall children may require water temperatures lessthan 120°F, 49°C. Local codes must be complied with!General Piping RequirementsEnsure that the water heater is equipped with bronzeheaders. Piping and components connected to the waterheater must be suitable for use with potable water. Thewater heater must not be connected to any heatingsystem piping or components previously used with anon-potable water heating appliance. No toxicchemicals, such as those used for boiler treatment, areto be introduced into any potable water used for spaceheating. If a hot water storage tank is used in thesystem, it must be equipped with a temperature andpressure relief valve that complies with ANSI Z21.22 orCAN-4.4 and CAN-4.6.NOTE: The storage tank must be located as closeto the water heater as possible to prevent excessivehead loss which will reduce flow.Water ChemistryThe required temperature rise across the water heateris based on water having a hardness between 5 and25 grains per gallon with a level of dissolved solids notexceeding 350 ppm. Water having a hardness less than5 grains can cause excessive corrosion of the heatexchanger. Water that has a hardness greater than 25grains per gallon and/or a level of dissolved solidsexceeding 350 ppm will require a recalculation of thepump size and temperature rise.A cupro-nickel heat exchanger may also be required.The manufacturer should be consulted when thesewater conditions are encountered. See Table 9A.