Carrier 60 Installation And Service Instructions Manual

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Carrier 60 Installation And Service Instructions Manual Manual pdf 26 page image

Table 5 — Typical Deadband RequirementsUNITCAPACITYSTEPSCOOLER DESIGN RANGE, F (C)5.0 (2.8) 10.0 (5.6) 15.0 (8.3)2 1.3 (0.7) 2.5 (1.4) 3.8 (2.1)3 0.8 (0.4) 1.7 (0.9) 2.5 (1.4)4 0.6 (0.3) 1.3 (0.7) 1.9 (1.1)Table 6 — Deadband SettingMIN. REQUIRED DEADBAND DEADBAND SETTING (F)F C0.5 to 1.5 0.28 to 0.83 1.02.0 1.11 2.02.5 1.39 2.53.0 1.67 2.83.5 1.94 3.04.0 2.22 3.74.5 2.50 4.010. Check compressor oil charge (should be visible inoil sight glass). Refer to Check Oil Charge section onpage 27.11. Be sure the compressor crankcase heater is warm (heatershould be on for 24 hours before starting the compres-sor). The crankcase heater must be firmly locked intothe compressor crankcase.12. Be sure the compressor is floating freely on the com-pressor springs (see Step 4 — Check Compressor Mount-ing and Connections section on page 3).13. For 30HL and HWA units with remote condenser, checkthe condenser fans for correct rotation. See instructionsshipped with the condenser.14. Be sure the unit is fully charged with refrigerant (seeCheck Refrigerant Charge section below).15. If unit is a brine unit, check to ensure proper brine con-centration is used to prevent freezing.Check Refrigerant ChargeWhen adding or removing refrigerant charge, circulatewater through condenser and cooler at all times to pre-vent freezing. Freezing damage is considered abuse andis not covered by Carrier warranty.The 30HK, HWB, HWC, and HWS units are shipped witha full refrigerant charge (see Tables 1A-2B). However, if itis necessary to add refrigerant, operate the unit for some timeat full capacity and then add charge until the sight glass isclear of bubbles. For maximum liquid subcooling, liquid levelshould be up to condenser end (30HK, HWC, HWS unitsonly). This usually requires additional refrigerant charge be-yond the amount to clear sight glass.The 30HL and HWA units (condenserless) are shipped witha refrigerant holding charge only. After chiller assembly iscompleted in the field, system must be fully charged. Whilethe unit is running at full capacity, add refrigerant until thesight glass is clear. R-22 is the normal refrigerant.Do not open the liquid valve or the compressor dischargevalve until there is a charge in remainder of system. A posi-tive pressure indicates a charge in system. With the unit op-erating at full load, check liquid line sight glass to be surethe unit is fully charged (bubbles in the sight glass indicatethe unit is not fully charged).If there is no refrigerant vapor pressure in the system, theentire system must be leak tested. After repairing leaks, evacu-ate the system before recharging. Follow approved evacu-ation procedures when removing refrigeration. Release re-maining pressure to an approved evacuated cylinder.The liquid charging method is recommended for com-plete charging or when additional charge is required.Be careful not to overcharge the system. Overchargingresults in higher discharge pressure with higher coolingwater consumption, possible compressor damage, andhigher power consumption.LIQUID CHARGING METHOD — Add charge to the unitthrough the liquid line service valve. Never charge liquidinto the low-pressure side of the system.1. Frontseat (close) condenser liquid line shutoff valve.2. Connect a refrigerant cylinder loosely to the charging valveconnection of the liquid line shutoff valve. Purge the charg-ing hose and tighten the connections.3. Open the charging valve.4. If the system has been dehydrated and is under vacuum,break the vacuum with refrigerant gas. For R-22, buildup system pressure to 58 psig and 32 F (400 kPa and0° C). Invert the refrigerant cylinder so that the liquidrefrigerant will be charged.5. a. For complete charge of 30HK, HWB, HWC, and HWSunits, follow charging by weight procedure. When chargeis nearly full, complete the process by observing thesight glass for clear liquid flow. The use of sight glasscharging is valid only when unit is operating at fullcapacity (no unloaders energized).b. For complete charge of 30HL and HWA units or whererefrigerant cylinder cannot be weighed, follow charg-ing by sight glass procedure. The use of sight glasscharging is valid only when unit is operating at fullcapacity (no unloaders energized).6. a. The 30HL and HWA condenserless units are shippedwith a holding charge only. After installation with thefield-supplied system high side, the complete systemshould be charged until the sight glass is clear (withthe unit running at full capacity). To achieve maxi-mum system capacity, add additional charge equal tothe difference between the condenser optimal chargeand the condenser minimum charge, which can be ob-tained from the charge data provided in the condenserinstallation instructions.b. To ensure maximum performance of 30HWB units,raise the compressor saturated discharge temperature(SDT) to approximately 105 F (40.6 C) by throttlingthe condenser water intake. Add charge until there isapproximately 15 to 17° F (8.3 to 9.4° C) of systemsubcooling (SDT minus actual temperature entering thethermostatic expansion valve).c. To ensure maximum performance of 30HK, HWC, andHWS units, raise the compressor saturated dischargetemperature (SDT) to approximately 103 F (39.4 C)by throttling the condenser water intake. Add chargeuntil there is approximately 8 to 10° F (4.4 to 5.6° C)for 30HK units or 12 to 14° F (6.7 to 7.8° C) for 30HWC,HWS units of system subcooling (SDT minus actualtemperature entering the thermostatic expansion valve).26