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Hersteller: Maytag Dateigröße: 792.29 kb Dateiname: H-IM-RACC.pdf Unterrichtssprache:

Typical Wiring Diagram for 208-230/1/60 with Fan Cycling. Models 049-080; 10-16Models 008-040; 1-8Models 105-133; 21-26TERMINALBOARDT3T2T1208-230V/3 phase/60HzM1M2M3FAN MOTORS460V/3 phase/60Hz Diagram 4. Typical Wiring Diagram for 208-230-460/3/60 TERMINALBOARDT3T2T1208-230V/3 phase/60HzGNDT2BOARDTERMINALT1M1C1C1M2C2FCCCOMNCC2M3C3FCCCOMNCC3FAN MOTORSCONTACTOR COILSTHERMOSTATS OR PRESSURE CONTROLSCONTACTORSCONTROL CIRCUIT* Models 049-080; 10-16Models 105-133; 21-26460V/3 phase/60Hz Diagram 5. Typical Wiring Diagram for 208-230-460/3/60 with Fan Cycling CONTROL CIRCUIT: May be 24 volt, 120 volt, or 230 volt (as specified). WARNING: There may be more than one source of electrical current in this unit. Do not service before disconnecting all power supplies. Start Up Check for proper fan rotation. Air is drawn through the coil on all units. Be sure the fans turn freely. Rotation of the motors and blades should be in a clockwise direction looking at the unit from the blade side. On three-phase units, it may be necessary to reverse two of the three power leads to the unit. NOTE: The manifold assembly is not designed to support field piping. Any damages to the condenser due to excessive weight, pressure or vibration will not be covered by standard warranty. Operation Winter Operation Head Pressure Control The capacity of an air-cooled condenser varies with the difference between the entering air dry bulb temperature and the condensing temperature of the refrigerant. Because air temperature in some regions varies as much as 100 degrees from summer to winter, some means must be employed to keep the condensing temperature sufficiently high to ensure proper operation of the refrigerant expansion valve during low ambient operation, and also allow sufficient capacity so that excessively high condensing temperatures do not result during high ambient conditions. The low limit of the head pressure is dependent upon the required pressure drop across the thermostatic expansion valve. For normal air conditioning applications, head pressure should be maintained above a condensing temperature corresponding to 90°F. This corresponds to a normal lower limit of about 60°F ambient air. Because air conditioning is not normally required at these lower ambient temperatures, condenser head pressure control may not always be necessary. However, for those applications below 60°F ambient air temperature, two methods of condenser head pressure control are available to meet specific job requirements and engineer/ owner preference: Fan Cycling, Variable Speed and Flooded Head Pressure Control (FHP). Fan Cycling Method This is an automatic winter control method and will maintain a condensing pressure within reasonable limits by cycling fan motors in response to outside air temperature entering the condensing coil. When voltage other than 230/208 is supplied to the unit, a transformer will be provided for field installation. Electrical protection must be provided for this transformer. Fan Cycling Operation and Installation The fan cycling control package consists of a weather-tight enclosure with motor starting contactor(s), as required, and thermostat(s). The contactor coil is 24 volts, 115 volts or 240 volts as ordered. The thermostats and contactors are wired as shown on Diagrams 3 and 5. Factory-installed packages are mounted on the unit and have all motor connections completed. Field wiring consists of connecting this panel to a power supply and fused disconnect(s) together with the control circuit to the contactor coils. Fan cycling is suitable for outside temperatures above those shown in Table 4. The thermostat should be field set to shut off the fan when the condensing temperature is reduced to approximately 90°F. Where operation at ambients below the range shown on Table 4 were required, FHP must be added. Table 5 lists approximate settings for several system T.D.’s. These settings are approximate as they do not ta...

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