Assessments - 2, GPA: 4 ( )

Fabricante : Lennox International Inc. Arquivo Tamanho: 1.27 mb Arquivo Nome : Língua de Ensino:

If a disposable filter is used, use the information provided in Table 2 when sizing the disposable filter. Minimum Required Surface Area for Disposable Filters Model Number Filter Area (minimum) PWC183 -480 square inches PWC24,3 480 square inches Table 2 Thermostat The room thermostat should be located on an inside wall where it will not be subject to drafts, sun exposure or heat from electrical fixtures or appliances. Follow the manufacturer's instructions enclosed with the thermostat for general installation procedures. Color coded insulated wires (#18 AWG) should be used to connect the thermostat to the unit. Electrical Connections All wiring must be done In accordance with the National Electrical Code (NEC), ANSl/NFPA No. 70 (latest edition); Canadian Electrical Code CSA C22.2 Part I (latest edition); or local codes, where they prevail. Any alteration of internal wiring will void certification and warranty. Units are factory wired for a 230 volt power supply. If power supply is 208 volts, it will be necessary to change a wire connection on unit transformer from 240 volt terminal to 208 volt terminal as shown on the wiring diagram. Usewiringwithatemperaturelimitation of 75 =C minimum. Run the 208 or 230 volt, 60 hertz electric power supply through a fused disconnect switch to the control box of the unit and connect as shown in the wiring diagram located on the inside of the control access panel. The unit must be electrically grounded in accordance with local codes or, in the absence of local codes, with the National Electrical Code ANSI/NFPA No. 70 (latest edition) or CSA C22.2 Part 1 (latest edition). Power supply to the unit must be NEC Class 1 and must comply with all applicable codes. A fused disconnect switch should be field provided for the unit. The switch must be separate from all other circuits. If any of the wire supplied with the unit must be replaced, replacement wire must be of the type shown on the wiring diagram. Electrical wiring must be sized to minimum circuit ampacity marked on the unit. Use copper conductors only. Each unit must be wired with a separate branch circuit and be properly fused. OPERATION Sequence of Operation Cooling When the thermostat is in the cooling mode, the O circuit is powered which energizes the reversing valve. Upon cooling demand, the thermostat closes circuit R toY and G. Closing R to Y closes the unit contactor, starting the compressor and outdoor fan. The thermostat automatically closes R to G circuit which also brings on the indoor blower at the same time. Upon satisfying cooling demand, the thermostat will open the above circuits and open the main contactor, stopping the compressor and outdoor fan. If the unit is equipped with a time delay, the blower will continue to operate for 90 seconds which improves system efficiency. Heating Upon heating demand, the thermostat closes circuit R to Y, which closes the unit contactor, starting the compressor and outdoor fan. The reversing valve is not energized in the heating mode. -The thermostat again automatically brings on the indoor fan at the same time. The second stage of the thermostat closes circuit R to W, which closes the unit sequencers, bringing the auxiliary electric heat on. Upon satisfying heating demand, the thermostat opens the above circuits and stops unit operation. Defrost Cycle If the outdoor ambient conditions are such that frost forms on the outdoor coil, the defrost control monitors the need for and initiates and terminates defrost cycles as necessary to maintain system performance. The defrost control is time/temperature initiated and temperature terminated with a maximum defrost time (time-out) of 10 minutes. Time between defrost cycles is preset at 60ominute intervals at the factory, but can be field adjusted between 30, 60 or 90 minutes. To field adjust time between defrost cycles, place defrost time plug in the proper position (see Figure 3). For best performance in Region IV, the PWC243 defrost interval should be adjusted to 30 minutes. Defrost control will initiate a defrost cycle if the time period has elapsed and the defrost sensor sees a temperature below freezing. At the start of a defrost cycle, the defrost control will energize the reversing valve solenoid, shifting the reversing valve and de-energizing the outdoor fan. The defrost relay will also close, energizing auxiliary heat for increased comfort during defrost. The unit will remain in defrost mode until the defrost sensor has determined that the frost has been removed from the coil or a 10minute time period has elapsed. The defrost control is also equipped with a setof pins to aid in troubleshooting of the defrost system (see Figure 3). The following is a brief outline of the testing of the defrost system. . Defrost sensor must be closed, 32°F o...

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