Stimmen - 2, Durchschnittliche Bewertung: 3.5
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Anleitung Zusammenfassung
For example, in Table 2, add .67 x 10 lbs (4.5 kg) (approximately 6.7 lbs [3.0 kg]) for the 67% circuit. Refer to Table 6 for condenser coil refrigerant circuit data. Check Operation of Condenser Fan Motor Controls and Rotation of Fans — Rotation should be clockwise as viewed from top of unit. A CAUTION To prevent personal injury, be sure wire fan guards are secured in place over each fan before starting the unit. IMPORTANT. Check for proper fan rotation (clockwise viewed from above). If rotation needs to be reversed on one motor, disconnect main power supply and switch motor leads at the fan contactor. If rotation needs to be reversed on all motors, disconnect main power supply and switch two leads at TB1. SERVICE Cleaning Condenser Coils — Clean coils with a vacuum cleaner, fresh water, compressed air, or a bristle brush (not wire). Units installed in corrosive environments should be cleaned as part of a planned maintenance schedule. In this type of application, all accumulations of dirt should be cleaned off the coil. A CAUTION Do not use high-pressure water or air. Damage to fins may result. Condenser Fans — Each fan is supported by a formed wire mount bolted to the fan deck and covered with a wire guard. The exposed end of the fan motor shaft is protected by grease. If the fan motor must be removed for service or replacement, be sure to grease fan shaft and reinstall fan guard. For proper performance, fan should be 7/8 in. (22 mm) below the top of the venturi on the fan deck for 60 Hz units, or 1/2 in. (13 mm) to top of the fan hub for 50 Hz units. Tighten set screws to 15 ± 1 ft-lbs (20 ± 1.3 N-m). Figure 31 shows the proper position of the mounted fan. After servicing condenser fan motors, recheck their rotation. See the preceding Start-Up section. Lubrication — Fan motors have permanently lubricated bearings. Head Pressure Control — Reduces condensing capacity under low ambient temperature conditions. See Fan Cycling section below. FAN CYCLING — The capacity of an air-cooled condenser increases with increased temperature difference (defined as entering saturated condenser temperature minus entering outdoor-air temperature) and decreases with decreased temperature difference. A drop in entering outdoor-air temperature results in a lower saturated condensing temperature. When outdoor-air temperature drops below the minimum temperatures listed in Table 7 for standard units, additional head pressure control is required. Model 09DK units have fully automatic intermediate-season head pressure control through condenser fan cycling using electromechanical fan cycling controls. Standard head pressure controls regulate the 100 and 50/50% condenser capacity applications. Head pressure can also be controlled by fan cycling controls supplemented by the accessory Motor-master® III solid-state head pressure control. See Motor-master III installation instructions for more information. Other circuit split applications (67/33, 33/33/33, 33/33/17/17% capacity splits) require the accessory fan control kit which includes a control panel and additional fan cycling pressure switches. See fan control installation instructions for more information. In the standard control scheme, fans 1 and 2 are on when there is a call for cooling from the respective coil circuits. Fans 1 and 2 are non-cycling. On 054 and 064 units, fans 3 and 4 are controlled by using a fan cycling pressure switch on each of the primary coil circuits in response to condensing pressure. On 074-094 units, fans 3 and 4 are controlled using a fan cycling pressure switch in each of the primary coil circuits in response to condensing pressure. Fans 5 and 6 are controlled by using two air temperature switches, which respond to the outdoor ambient temperature. The air temperature switches are located on the control box shelf. For temperature and pressure setting details, see Table 8. TOP OF VENTURI TOP OF VENTURI ON FAN DECK ON FAN DECK NOTE: Fan rotation is clockwise as viewed from top of unit Fig. 31 — Condenser Fan Adjustment 32 The fan cycling pressure switch controls the fans as follows: Fans 3 and 4 are on above 260 ± 15 psig (1793 ± 103 kPa) and off below 160 ± 10 psig (1103 ± 69 kPa). If pressure is rising between 160 psig (1103 kPa) and 260 psig (1793 kPa), fans 3 and 4 are off. If pressure is falling from 260 psig (1793 kPa) to 160 psig (1103 kPa) fans 3 and 4 are on. The air temperature switch controls the fans as follows: On the 074-094 condensers, below 70 ± 3 F (21.1 ± 1.7 C) outdoor ambient, fans 5 and 6 are off; above 80 ± 3 F (26.7 ± 1.7 C) fans 5 and 6 are on. Between 70 F (21.1 C) and 80 F (26.7 C), whether fans 5 and 6 are on or off depends on whether temperature is rising or falling. If the temperature is rising from 70 F (21.1 C) to 80 F (26.7 C), fans 5 and 6 are off. If the temperature is falling from 80 F (26.7 C) to 70 F (21.1 C), fans 5 and 6 are on. Table 6 — Condenser Coil Refrigerant Circuit Data UNIT 09DK0...