Boiler Manual - Weil-McLain

GV90+ gas-fired water boiler — Boiler ManualMultiple boiler water piping (continued)Figure 34 Piping layout — typical for multiple GV90+ boilers, with DHW storage heaters (4-boiler system)Suggested DHWboiler-side pipesizing (for max 0.04feet head loss per foot oftotal equivalent length,TEL)Flow rate Size Flow rate Size1 – 4 gpm ¾” 22 – 45 gpm 2”4 – 8 gpm 1” 45 – 75 gpm 2½”8 – 14 gpm 1¼” 75 - 140 gpm 3”14 – 22 gpm 1½” 140 – 290 gpm 4”1 Flow/check valve (each boiler)2 Isolation valves (when used)3 Caps4 Easy-Fit® Manifold (supply) — layout andsize per page 245 Easy-Fit® Manifold (return) — layout and sizeper page 246 Primary circulator7 Expansion tank (diaphragm type)8 System air eliminator9 System automatic air vent16 Cold water fill line — see Figure 32, page 25for typical components18 System supply19 System return20 Boiler relief valve and discharge piping,installed per GV90+ Boiler ManualLegend — Figure 3421 Indirect-fired storage water heaters — Example is shown with a boilerwater circulator on each water heater. Alternatively, the water heaters couldbe connected with reverse return piping, using a common circulator.22 Boiler water inlet23 Boiler water outlet24 DHW boiler-side circulators25 DHW boiler-side return Easy-Fit® Manifold26 DHW boiler-side supply Easy-Fit® Manifold27 Flow/check valves (to prevent induced or gravity flow in heating system orDHW piping)28 Check valve to prevent heat migration in heating system29 Drain valves30 Sensor for BCP (boiler control panel), when usedNote: See water heater manual for DHW piping — The DHW piping must alsobe manifolded together since the boiler-side piping is manifolded. If DHWheaters supply separate DHW circuits, provide an individual circulator foreach water heater, and control each circulator by its water heater’s aquastat.This piping is suggestedonly. Thelayout above should be controlledwith a boiler sequencing panel thatprovides DHW operation as well.Wire the heating system circulatorto operate only on call for heat. Alternatively,use the boiler sequencingpanel to provide domestic priorityby disabling the heating system circulatorany time there is a DHW callfor heat. The boiler internal circulatorsoperate on any call for heat,whether heating system or DHW.Offset the DHW boiler-side supplyand return manifolds as shown sothe total run of pipe and fittings toeach of the water heaters is approximatelyequal.Part number 550-142-054/1211 27