Carrier GEMINI 38APD025-100 Operating And Service Manual

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Carrier GEMINI 38APD025-100 Operating And Service Manual Manual pdf 34 page image

34Table 15 — Preliminary Puron Refrigerant (R-410A)Charge, lb (kg)NOTES:1. Preliminary charge is based on 25 ft (7.6 m) of interconnecting liquid linepiping between indoor and outdoor units.2. For liquid line piping longer than 25 ft (7.6 m), use the followinginformation:1 /2 in. (12.7 mm) liquid line — 0.6 lb per 10 linear ft (0.27 kg per 3 m)5 /8 in. (15.9 mm) liquid line — 1.0 lb per 10 linear ft (0.45 kg per 3 m)7 /8 in. (22.2 mm) liquid line — 2.0 lb per 10 linear ft (0.91 kg per 3 m)1 1 /8 in. (28.6 mm) liquid line — 3.5 lb per 10 linear ft (1.59 kg per 3 m)Adjust Refrigerant ChargeDue to the compact design of microchannel heat exchang-ers, refrigerant charge is reduced significantly. As a result,charging procedures for MCHX units require very accuratemeasurement techniques. Charge should be added in smallincrements. Using cooling charging charts provided, add orremove refrigerant until conditions of the chart are met. Asconditions get close to the point on the chart, add or removecharge in 1/4 lb increments until complete. Ensure that all fansare on and all compressors are running when using chargingcharts. If charging at low outdoor ambient, the condenser coilcan be partially blocked in order to increase head pressure.With all fans operating and all compressors on the circuitbeing serviced operating at full capacity, adjust the refrigerantcharge in accordance with the unit charging charts in Fig. 35-56. Charge vapor into compressor low-side service port locatedon the suction service valve. Measure pressure at the liquid lineservice valve, making sure a Schrader depressor is used. Also,measure liquid line temperature as close to the liquid servicevalve as possible. Add charge until the pressure and tempera-ture conditions of the charging chart curve are met. If liquidpressure and temperature point fall above curve, add charge. Ifliquid pressure and temperature point fall below curve, reducethe charge until the conditions match the curve.If the sight glass is cloudy, check refrigerant charge again.See Fig. 57 and 58. Ensure all fans and compressors on the cir-cuit being serviced are operating. Also ensure maximum allow-able liquid lift has not been exceeded. If the sight glass iscloudy, a restriction could exist in the liquid line. Check for aplugged filter drier or partially open solenoid valve. Replace orrepair, as needed.38AP UNIT SIZE CIRCUIT A CIRCUIT B38APS025 24 (10.9) —38APD025 12 (5.6) 12 (5.6)38APS027 26 (11.6) —38APD027 13 (6.0) 13 (6.0)38APS030 29 (12.9) —38APD030 14 (6.5) 14 (6.5)38APS040 39 (17.7) —38APD040 21 (9.5) 17 (7.8)38APS050 48 (21.5) —38APD050 22 (9.9) 26 (11.6)38APD060 27 (12.1) 29 (12.9)38APD070 29 (12.9) 33 (15.1)38APD080 29 (12.9) 46 (20.7)38APD090 39 (17.7) 46 (20.7)38APD100 46 (20.7) 46 (20.7)CAUTIONNever charge liquid into the low pressure side of system.Do not overcharge. During charging or removal of refriger-ation, be sure indoor fan system is operating. Failureto comply could result in personal injury or equipmentdamage.CAUTIONCharging procedures for MCHX (microchannel heatexchanger) units require very accurate measurement tech-niques. Charge should be added in small increments. Usingcooling charging charts provided, add or remove refriger-ant until conditions of the chart are met. As conditions getclose to the point on the chart, add or remove charge in1/4 lb increments until complete. Ensure that all fans are onand all compressors are running when using chargingcharts. Failure to comply may result in equipment damage.