RBI Futera XLF Installation And Operation Instructions Manual

Also see for FUTERA XLF Series: Manual Control manual Manual Installation and operation instructions

RBI Futera XLF Installation And Operation Instructions Manual Manual pdf 18 page image

Finned copper tube gas boilers & water heaters – Boiler Manual18The maximum allowable flow rate through a FuteraXLF boiler is 260 GPM, 16.4 L/s when equippedwith copper tubes. A cupronickel heat exchanger allowsfor 315 GPM, 19.9 L/s.Table 7 Temperature Rise TableModelNumber∆T = 20oF ∆T = 11.1oCFlow Rate Pres. Drop Flow Rate Pres. DropGPM Ft L/s kPa2500 217.5 10.05 13.7 29.63000 261.0 15.20 16.5 44.83500 304.5* 20.26 19.2* 59.74000 NA NA NA NA5000 NA NA NA NAModelNumber∆T = 25oF ∆T = 13.9oCFlow Rate Pres. Drop Flow Rate Pres. DropGPM Ft L/s kPa2500 174.0 6.45 11.0 19.03000 208.8 9.73 13.2 28.73500 243.6 13.40 15.4 39.54000 278.4* 17.30 17.6* 51.05000 NA NA NA NAModelNumber∆T = 30oF ∆T = 16.7oCFlow Rate Pres. Drop Flow Rate Pres. DropGPM Ft L/s kPa2500 145.0 3.71 9.1 10.93000 174.0 6.75 11.0 19.93500 203.0 9.56 12.8 28.24000 232.0 12.00 14.6 35.45000** 290.0 21.20 18.3 62.5ModelNumber∆T = 35oF ∆T = 19.4oCFlow Rate Pres. Drop Flow Rate Pres. DropGPM Ft L/s kPa2500 124.3 2.79 7.8 8.23000 149.1 4.65 9.4 13.73500 174.0 7.19 10.9 21.24000 198.9 10.48 12.5 30.95000** 248.6 19.70 15.7 58.0* This flow rate exceeds the recommended maximum for a boiler witha standard copper heat exchanger. Use a greater temperature rise orconsult manufacturer. Consider a cupro-nickel heat exchanger, becauseits maximum flow rate is 315 GPM.** Cupronickel standard on Model 5000 only.Low water cutoffIf a boiler is installed above any radiation elements it must be fittedwith a low water cutoff device.Refer to the wiring diagram supplied with the boiler/water heater forproper wiring connections.Expansion tank and air separatorAn expansion tank or other means to control thermal expansionmust be installed in the heating system. An expansion tank must beinstalled close to the boiler on the suction side of the pump. An airscoop and automatic air vent must also be installed to eliminate airtrapped in the system.Primary/secondary pipingBoilers connected to heating systems using zone valves, zone pumps,or systems that have excessive flow rates or return water temperaturesless than 140oF, 60oC must be isolated from these systems to protectthe boiler.Variable water flowsFigure 10, shows a typical primary/secondary piping system. Adedicated pump is used to maintain a constant water flowthrough the boiler. This boiler pump is sized to overcome the headloss of the boiler and near-boiler piping system while supplying theflow rate required to maintain the desired temperature rise across theboiler heat exchanger. The system pump is sized to provide therequired flow to the heating system. The boiler piping connectionsto the heating system piping must be a maximum 6 pipe diametersbetween centers to ensure zero pressure drop in the primary system.Low return water temperaturesTo prevent the problems associated with condensation of theproducts of combustion due to low return water temperatures aprimary/secondary piping system with a bypass and bypass valvemust be installed, see Figure 11. The bypass system must be sizedthe same as the secondary piping. The primary and secondarypumps should be sized to provide the required flow through eachsystem. The boiler piping connections to the heating system pipingmust be a maximum 6 pipe diameters between centers to ensurezero pressure drop in the primary system.Multiple boiler systemsSystems using multiple boilers can also be installed using a primary/secondary manifold system, Figure 13.Piping for use with cooling unitsThe boiler, when used in connection with a refrigeration system, mustbe installed so the chilled medium is piped in parallel with the boiler.Appropriate valves must be used to prevent the chilled water fromentering the boiler.