Évaluations - 4, GPA: 4
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Facilité d'utilisation
The relief valve is set to open at 30 psi. If the valve is replaced, the replacement must have a relief capacity in excess of the DOE heating capacity for the boiler. Pipe the discharge of the relief valve to a location where water or steam will not create a hazard or cause property damage if the valve opens. The end of the discharge pipe must terminate in an unthreaded pipe. If the relief valve discharge is not piped to a drain, it must terminate at least 6 inches above the floor. Do not run relief valve discharge piping through an area that is prone to freezing. The termination of the relief valve discharge piping must be in an area where it is not likely to become plugged by debris. 2) The fitting in which the gauge, relief valve and LWCO are to be mounted must not be moved from the factory specified location (Figure 2.1). DANGER • PIPE RELIEF VALVE DISCHARGE TO A SAFE LOCATION. • DO NOT INSTALL A VALVE IN THE RELIEF VALVE DISCHARGE LINE. • DO NOT INSTALL RELIEF VALVE IN A LOCATION OTHER THAN THAT SPECIFIED BY THE FACTORY • DO NOT PLUG THE RELIEF VALVE DISCHARGE. 31 3) The return piping may be connected into the boiler through the back or sides of the boiler by rotating the drain elbow and routing the return piping through the appropriate knockout. 4) Circulator (Required) - Usually at least two circulators will be required to properly install a BWC Series boiler. See previous section (System Design) for information on sizing the circulators. 5) Expansion Tank (Required) - If this boiler is replacing an existing boiler with no other changes in the system, the old expansion tank can generally be reused. If the expansion tank must be replaced, consult the expansion tank manufacturer’s literature for proper sizing. 6) Fill Valve (Required) - Either a manual or automatic fill valve may be used. The ideal location for the fill is at the expansion tank. 7) Automatic Air Vent (Required) - At least one automatic air vent is required. Manual vents will usually be required in other parts of the system to remove air during initial fill. 8) Manual Reset High Limit (Required by some codes) - This control is required by ASME CSD-1 and some other codes. Install the high limit in the boiler supply piping just above the boiler with no intervening valves. Set the manual reset high limit to 200°F. Wire the limit per Figures 9.1 & 9.2 in the Wiring section. 9) Flow Control Valve (Required) - The flow control valve prevents flow through the system unless the circulator is operating. Flow control valves are used to prevent gravity circulation or “ghost flows” in circulator zone systems through zones that are not calling for heat. 10) Isolation Valves (Recommended) - Isolation valves are useful when the boiler must be drained, as they will eliminate having to drain and refill the entire system. 11) Drain Valve (Required) - The drain valve is installed on the return tee located in the lower vestibule compartment as shown in Figure 8.2. 12) Low Water Cut-off (Required) - The low water cut-off supplied with this boiler must not be removed. D. Piping for Special Situations 1) Systems containing oxygen - Many hydronic systems contain enough dissolved oxygen to cause severe corrosion damage to an aluminum boiler such as the BWC. Some examples include: • Radiant systems that employ tubing without an oxygen barrier. • Systems with routine additions of fresh water. • Systems which are open to the atmosphere. If the boiler is to be used in such a system, it must be separated from the oxygenated water being heated with a heat exchanger as shown in Figure 8.13. Consult the heat exchanger manufacturer for proper heat exchanger sizing as well as flow and temperature requirements. All components on the oxygenated side of the heat exchanger, such as the pump and expansion tank, must be designed for use in oxygenated water. 2) Piping with a Chiller - If the boiler is used in conjunction with a chiller, pipe the boiler and chiller in parallel as shown in Figure 8.14. Use isolation valves to prevent chilled water from entering the boiler. 3) Air Handlers - Where the boiler is connected to air handlers through which refrigerated air passes, use flow control valves in the boiler piping or other automatic means to prevent gravity circulation during the cooling cycle. 32 1 Bimini Boiler 2 Indirect IWH Water Heater (If Used) 3 Isolation Valve 4 Swing Check Valve 5 Central Heating Secondary Circulator 6 IWH Circulator 7 Central Heating Primary Circulator 8 Plate Heat Exchanger 9 Air Separator 10 Automatic Air Vent 11 Expansion Tank 12 Automatic Fill Valve 13 Cold Water Line 14 Relief Valve 15 Relief Valve Discharge Piping 16 Drain Valve 17 Primary / Secondary Connection Figure 8.13: Isolation of the Boiler From Oxygenated Water with A Plate Heat Exchanger Figure 8.14: Chiller Piping 33 IX Wiring WARNING All wiring and grounding must be done in accordance with the authority having jurisdiction or, in th...