valutazioni - 2, GPA: 5 ( )

Produttore : Carrier File Size : 293.47 kb File Nome : Lingua di insegnamento:

PRESSURE DIFFERENTIAL (difference between cylinder load and unload points) is adjustable from 6 to 22 psig (41.4 to 152 kPa). To adjust, turn pressure differential adjustment screw (Fig. 12) counterclockwise to its back stop position. In this position, differential is 6 psig (41.4 kPa). Next, turn adjustment clockwise to desired pressure differential setting. Every full turn clockwise increases differential by 1.5 psig (10.3 kPa). Head Pressure Control — Fan cycling is a standard feature. The no. 2 fan cycles in response to changes in liquid pressure. The switch cycles the fan off at 126 ± 4 psig (869 ± 28 kPa) as pressure decreases, and cycles it back on at 257 (+5, .0) psig (1772 [+103, .0] kPa). Fig. 12 — Compressor Capacity Control Unloader Time Guard II Circuit — Prevents short-cycling by providing a delay of approximately 5 minutes before restarting compressor after shutdown from safety device action. On start-up, the Time Guard II timer causes a delay of approximately 3 seconds after thermostat closes. On compressor shutdown, the timer recycles for approximately 5 minutes. During this time, the compressor cannot restart. Refer to Fig. 13 and to label diagram on unit. Fig. 13 — Timer Sequence Chart Winter-Start Control (If Required) — Install Accessory Package 38AE900021. Crankcase Heater — The heater prevents refrigerant migration and compressor oil dilution during shutdown whenever compressor is not operating. It is wired into the control circuit, and cycles with the compressor; the heater is off when compressor is running, and on when compressor is off. Both compressor service valves must be closed whenever the crankcase heater is deenergized for more than 6 hours. The crankcase heater is operable as long as the control circuit is energized. 13 38AKS02438AKS024 Outdoor 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 motor shaft is covered with a rubber boot. In case a fan motor must be repaired or replaced, be sure the rubber boot is put back on when the fan is reinstalled and be sure the fan guard is in place before starting the unit. Figure 14 shows the proper position of the mounted fan. Fan motors have permanently lubricated bearings. 38AE012,014,016 Fig. 14 — Outdoor Fan Lubrication FAN MOTORS have sealed bearings. No provisions are made for lubrication. COMPRESSOR has its own oil supply. Loss of oil due to a leak in the system should be the only reason for adding oil after the system has been in operation. See Oil Charge section. Cleaning Coils — The coils can be cleaned with a vacuum cleaner, washed out with water, blown out with low-pressure compressed air, or brushed (do not use wire brush). Fan motors are drip-proof but not waterproof. Clean outdoor coil annually or as required by location or outdoor air conditions. Inspect coil monthly, and clean as required. Fins are not continuous through coil sections; dirt and debris may pass through first section, become trapped between the 2 rows of fins (38AE012) or 3 rows of fins (38AE014,016, 38AKS024) and restrict outdoor airflow. Use a flashlight to determine if dirt or debris has collected between coil sections. Clean coil as follows: 1. Turn off unit power. 2. Remove screws holding rear corner posts and top cover in place. Pivot top cover up 12 to 18 in. (305 to 457 mm) and support with a rigid support. See Fig. 15. 3. Remove clips securing tube sheets together at the return bend end of the coil. Carefully spread the ends of the coil rows apart by moving the outer sections. See Fig. 16. 4. Using a water hose, or other suitable equipment, flush down between the sections of coil to remove dirt and debris. 5. Clean the remaining surfaces in the normal manner. 6. Reposition outer coil sections. 7. Reinstall clips which secure tube sheets. 8. Replace top cover and rear corner posts. Fig.15—PivotandSupportTopCover Fig.16—CoilCleaning(Typical) 14 TROUBLESHOOTING PROBLEM SOLUTION COMPRESSOR DOES NOT RUN Contactor Open 1. Power off. 2. Fuses blown in field power circuit. 3. No control power. 4. Thermostat circuit open. 5. Time Guard. II device not operating. 6. Compressor circuit breaker tripped. 7. Safety device lock-out circuit active. 8. Low-pressure switch open. 9. High-pressure switch open. 10. Compressor overtemperature switch open. 11. Loose electrical connections. 12. Compressor stuck. Contactor Closed 1. Compressor leads loose. 2. Motor windings open. 3. Single phasing. 1. Restore power. 2. After finding cause and correcting, replace with correct size fuse. 3. Check secondary fuse(s); replace with correct type and size. Replace transformer if primary windings receiving power. 4. Check thermostat setting. 5. Check Time Guard II devices. 6. Check for excessive compressor current draw. Reset breaker; replace if defective. 7. Reset lock-out circuit at thermostat or circuit breaker. 8. Check for refrigerant undercharge, obstruction of indoor airflow, or whether comp...

Scarica la tua

Per scaricare, digitare 2 cifre :