Assessments - 3, GPA: 4 ( )

Fabricante : A.O. Smith Arquivo Tamanho: 364.31 kb Arquivo Nome : Língua de Ensino:

Constant circulation of water between the storage tank and the building is permissible as long as the water does not constantly flow through the heater. Only all bronze circulators are used with commercial water heaters. Although circulators are oiled and operated by the manufacturer, THEY MUST BE OILED AGAIN BEFORE OPERATED. Oil the three oil cups (2 on the motor, 1 on the pump) as instructed by manufacturer. See fig. 4. Thereafter, lubricate the three oil cups at least once every 4 months. TYPICAL CIRCULATING PUMP FIGURE 4 Use 2 or 3 teaspoonsful in bearing oil cups, and 10 or 12 drops in the motor oil cups. Use no. 20 non-detergent motor oil. Follow the same oiling procedure if a replacement circulator is installed into the system. TANK TEMPERATURE CONTROL (Not Supplied) DANGER USE ANTI-SCALD VALVE(S) in the hot water system to reduce the risks of scalds at points of use such as lavatories, sinks and bathing facilities. The tank temperature control is located in the lower portion of the hot water storage tank, see PIPING DIAGRAMS. It is the primary operating control of the system and regulates the water temperature in the tank. The storage tank thermostat should have contact ratings that exceed the maximum electrical requirements of the system. Typically, the thermostat should have motor full load and locked rotor current ratings which exceed the total amount of current required to drive the pump(s) controlled by the thermostat. The thermostat should have a temperature range of 1000F (37.7°C) to 1800F (82.2°C) or more. The preferred initial setting for the storage tank thermostat is 1200F (48.8°C). However, for normal use, the thermostat should be adjusted to the lowest setting which produces an acceptable hot water supply temperature. This will always give the most energy efficient operation. Do not adjust the thermostat to achieve a storage temperature of 190oF (87.7°C) or above. This action may cause the automatic gas shutoff control to activate shutting down the heater. Intermittent ignition device and circulator start and stop simultaneously as the tank thermostat contacts open and close. This basic action, water flowing whenever the burner operates, must not be altered. SAFETY FLOW SWITCH (Not Supplied) The safety flow switch is a safety device installed at the water outlet of the unit to prevent main burner operation in the event of inadequate water flow through the unit. An accessory package A.O.S. No. 211480 containing a safety flow switch is available for this application. This switch may be mounted in a horizontal pipe line or a vertical pipe line with upward water flow. Do not install the switch where the water flow is downward. For proper performance mount the switch in a section of pipe where there is a straight run of at least 5 pipe diameters on each side of the flow switch (i.e. do not locate adjacent to valves, elbows, orifices, etc.). The flow switch shall be mounted in a standard 1" x 1" x 1" tee for a 1" pipe application. For larger pipe sizes use a reducing tee in order to keep the switch as close to the pipe as possible. Install the flow switch in the branch (top) opening of the reducing tee and provide adequate paddle length in the flow stream. For example in a 2" pipe installation use a 2" x 2" x 1" reducing tee. For 1", 2" or 3" pipe use the paddle segments as supplied. For other pipe sizes (i.e. 1 1/4", 1 1/2", and 2 1/2") trim the paddle to the proper pipe size, see fig. 5. If a standard tee is used, install a face or hex bushing in the top opening. The paddle must be adjusted or trimmed to the size of the pipe in which it will be installed. 6 CAUTION: The paddle must be trimmed at the dotted arc. It must not touch the pipe or any restrictions when installed. FIGURE 5 CAUTION Any part of the paddle must not touch the pipe or any restrictions in the pipe. Screw the flow switch in position so the flat of the paddle is at right angles to the flow. The arrow on the side case must point in the direction of the flow. The safety flow switch may be field adjusted to obtain higher minimum flow rates than those shown in Table 5. To adjust the flow rate setting: 1. Remove the flow switch cover. 2. For higher flow rate—turn the range adjusting screw clockwise. 3. For lower flow rate—turn the range adjusting screw counterclockwise. CAUTION The switch is factory set at approximately the minimum flow rate, see Table 5. It must not be set lower than the factory setting as this may result in the switch failing to return at a “no flow” condition. 4. Replace the flow switch cover. TABLE 5 - SAFETY FLOW SWITCH SETTINGS The installer is cautioned to follow the manufacturer’s instructions exactly when inserting this switch into a pipe tee. This is necessary in order to assure positive action of the switch with water flow. Once the minimum flow rate (Table 5) through the heater is reached, the safety flow switch contacts close and consequently, main burner operation is achieved. DRAIN VALVE (Not Sup...

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