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Производитель: A.O. Smith Размер: 335.32 kb Название файла: Язык инструкции:

The system or primary circulator may or may not be controlled by the boiler sequencer. When this pump is operated through the first switch of any type of step controller, care should be taken to determine if a motor starter is needed due to insufficient switch capacity. If the primary pump is controlled by a manual switch or any other controllers, the electric current supply to the boiler group should be through the primary pump controller. The fast response of A.O. Smith boilers eliminates any need to maintain boiler temperature when the system is satisfied. Wiring should always prevent firing of boiler(s) when there is no water flow in the mains. Installation diagrams show safety flow switches in the outlet piping from each boiler as good protection against any boiler being fired when the boiler loop circulator is not in operation. These safety flow switches will also provide some protection if there is a loss of water. Multiple boiler installations are especially adapted to the use of outdoor reset for main water temperatures. This feature is not Figure 10. Single or Multiple Boiler Installation Diagram 16 mandatory but offers smooth, efficient operation of a modern system. Normal use of flow control valves is required to prevent cross circulation of zones as with any multiple pump system. Large systems with multiple boilers should include main water temperature controls (with or without outdoor reset) to sequence the boiler on and off, in relation to the load on the system. 24 VAC System Controller (Optional) GB models require a field supplied 24VAC operating control to be installed in the system such as: loop thermostat, indoor/outdoor reset control, sequencing panel, or energy management system. The connection for such devices is located in the 24 VAC junction box at the rear of the unit. A 24 VAC thermostat/aquastat can only be used as an "On/Off" switch for the unit. The actual controlling of the staging will be through either the inlet or tank probe. To use a 24 VAC system controller, dip switch "E" on the CCB must be switched to the "on" position. See figure 14. INTERNAL CONTAMINANTS The system must be internally cleaned and flushed after a new or replacement unit has been installed to remove contaminants that may have accumulated during installation. This is doubly important when a replacement unit is installed into an existing system where Stop Leak or other boiler additives have been used. All systems should be completely flushed with a grease removing solution to assure trouble-free operation. Pipe joint compounds, soldering paste, grease on tubing and pipe all tend to contaminate a system. Failure to clean and flush the system can cause solids to form on the inside of the heat exchanger, can produce acid concentrations that become corrosive, can allow excessive amounts of air or other gases to form which could block circulation, foul system accessories and damage circulator seals and impellers. It is recommended that after installation, the boiler and system when filled should include the proper percentage of cleaning solution related to approximate water volume of the system. Fire and circulate for about one hour and then flush clean with fresh water. Commercial grease removing solutions are available. Before operating the boiler, the entire system must be filled with water, purged of air and checked for leaks. Do not use Stop Leak or other boiler compounds. The gas piping must also be leak tested. THE WATER HEATER SHOULD BE LOCATED IN AN AREA WHERE THE GENERAL PUBLIC DOES NOT HAVE ACCESS TO SET TEMPERATURES. HOT WATER SUPPLY BOILER INSTALLATION WATER LINE CONNECTIONS Where excessive heat exchanger condensation exists due to continued low inlet water temperatures (below 120oF), a bypass balance loop must be installed (see figures 11 and 13). HARD WATER CONDITIONS Where hard water conditions exist, water softening or the threshold type of water treatment is recommended. This will protect the dishwashers, coffee urns, water heaters, water piping and other equipment. When water softening or water treatment is not practical, a comparatively easy method of periodic lime removal from the unit must be employed. WARNING LIME ACCUMULATION CAN REDUCE THE LIFE OF THE EQUIPMENT, REDUCE EFFICIENCYAND WASTE FUEL. BOILER FAILURE DUE TO LIME OR SCALE BUILDUP VOIDS THE WARRANTY. Tank Probe (Optional) In addition to the Inlet and Outlet/ECO Probes, units can be optionally equipped with a tank Probe. The connection for the tank probe is located in the 24VAC junction box at the rear of the unit. The tank Probe can be configured to control the staging of the unit. See Tank Probe Installation section below for additional information. TANK PROBE INSTALLATION PROCEDURE A tank probe is supplied with each hot water supply boiler (GW). To connect the tank probe to the boiler, remove the cover from the 24 VAC junction box at the rear of the unit. Connect the probe wires across terminals 1 & 2. (The wires leading to the...

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