Carrier 60 Installation And Service Instructions Manual

Also see for 60: Manual Service manual

Contents

Carrier 60 Installation And Service Instructions Manual Manual pdf 28 page image

DISCHARGE LINE CHECK VALVE — On all 30HL, HWAunits, a factory-supplied check valve is shipped with the unit(two valves are provided for 30HL units). The check valve(s)should be installed in the discharge line(s) downstream from,but close to, the compressor muffler. Install the valve in anyposition except bonnet down.The check valve(s) prevents backwards-migration of re-frigerant from the condenser(s) to the compressor(s) and coolerduring the compressor off cycle.HOT GAS BYPASS VALVE — On units equipped with thefactory-installed capacity reduction option (30HW only), ahot gas bypass valve is located between the discharge lineand the cooler entering-refrigerant line. A solenoid valve isinstalled in the equalizer line of the hot gas valve to allowthe temperature control to cycle the hot gas bypass function.The amount of capacity reduction achieved by the hot gasbypass valve may be altered by adjusting the spring tensionof the hot gas bypass valve. The total unit capacity shouldnot be reduced below 10% of the nominal rating.LIQUID LINE SOLENOID VALVE (30HL ONLY) — Thesolenoid valve closes when its circuit is inoperative, eitherfrom capacity control or from any safety trip.PRESSURE RELIEF DEVICES — All 30HK, 30HL, and30HW units are equipped with a compressor pressure reliefvalve located on the crankcase of the 06E compressor units(except for the 30HW018 units which have a compressordisplacement less than 50 cfm). The pressure relief valve opensat 450 psig (3103 kPa).The 30HK,HWC, and HWS units are also equipped witha high-side refrigerant pressure relief valve on the shell andtube condenser. The valve is set to open at the working pres-sure of the condenser, as shown in Table 7.The 30HWB does not have a condenser pressure reliefvalve, because the brazed-plate condenser is not considereda pressure vessel, as defined in ANSI/ASHRAE 15 (Ameri-can National Standards Institute/American Society of Heat-ing, Refrigerating, and Air Conditioning Engineers) safetycode requirements.For 30HL and HWA condenserless units, pressure reliefdevices designed to relieve at 450 psig (3103 kPa), must befield-supplied and installed in the discharge line piping afterthe muffler in accordance with ANSI/ASHRAE 15 safety coderequirements. Additional pressure relief valves, properly se-lected, must be field-supplied and installed to protect highside equipment and may be required by applicable codes.Most codes require that a relief valve be vented directlyto the outdoors. The vent line must not be smaller than therelief valve outlet. The condenser relief valves have a 5 ⁄8 -in.SAE (Society of Automotive Engineers, U.S.A.) flare connec-tion. The compressor relief valves have a 3⁄ 8-in. SAE Flareconnection. Consult ANSI/ASHRAE 15 for detailed infor-mation concerning layout and sizing of relief vent lines.All units have a factory-installed fusible plug in the suc-tion line which relieves on a temperature rise at 170 F(77 C) and one in the liquid line which relieves at 210 F (99 C).Table 7 — Pressure Relief Valve SettingsUNIT PRESSURE RELIEF VALVE SETTINGSPsig kPa30HK 385 265530HWC 365 251730HWS 335 2310Compressor and Unit Protective DevicesCIRCUIT BREAKER — There is a single circuit breakerper compressor in each unit. The circuit breaker(s) protectsthe compressor(s) against overloading, locked rotor condi-tions, and primary single phasing. If the circuit breaker(s)trips, determine the cause and correct it before resetting thebreaker(s).COMPRESSOR INTERNAL THERMAL PROTECTION —On the 30HW018 units, there is a sensor imbedded inthe compressor windings to detect an overtemperaturecondition.The thermostat opens and shuts off the compressor if thedischarge gas temperature exceeds 295 ± 5° F (146 ± 2.8° C).The thermostat will reset when the temperature drops to ap-proximately 250 F (121 C). However, the control modulewill keep the unit locked off until control power is manuallycycled off, then back on.NOTE: Compressor overtemperature protection for 30HK,HL units is accomplished by high and low pressure switchesand circuit breakers which are external to the compressors.CRANKCASE HEATERNever open or disconnect any switch that energizes thecrankcase heater, unless the unit is being serviced or willbe shut down for an extended period. After service orshutdown, energize the crankcase heater for 24 hoursbefore starting the compressor.IMPORTANT: The crankcase heater is located in thebottom corner of the compressor and held in place bya bracket. The heater must be tight to prevent it frombacking out of the heater well. The heater eventuallyburns out if exposed to the air for an extended period.The heater in each compressor prevents absorption of liq-uid refrigerant by the compressor oil when the compressoris not operating. The heater is wired into the normally closedcontacts of the compressor control relay so that it energizesonly when the compressor is not operating. The heater is125 w, 115 v on all 60 Hz units; 230 v on 50 Hz 30HK, HLunits; and 115 v on 50 Hz 30HW units.OIL PRESSURE SAFETY SWITCH (OPS) — One OPS percompressor is standard on all 30HL and HWA units, and onall units equipped with the medium temperature brine op-tion. One is located in each compressor terminal box withcapillaries to the crankcase and oil pump. The switch is alsooffered as an accessory (part number 30HW900006) for stand-ard 30HK, HWB, HWC, and HWS units. When used, theOPS is monitored by the unit control module. If at any timeafter the compressor is started, the OPS is open for morethan 2 minutes, the compressor shuts down and is locked offuntil control power is manually cycled to OFF, then back tothe ON position. The OPS cuts out at 5 ± 1 psig (34.5 ±6.9 kPa), and has a maximum cut-in of 9.5 psig (65.5 kPa).Check Unit SafetiesCONTROL MODULE — The unit control module is lo-cated in the control section of the control box. See Fig. 19and 20. It performs several functions. The control modulehas a built-in compressor anti-short-cycle timer which willnot allow a compressor to restart until 5 minutes have elapsedsince the previous shutdown.On 30HL and HWA units (and 30HK, HWB, HWC, andHWS units equipped with the oil pressure safety switch [OPS]accessory), the compressor oil pressure and low-pressureswitch(es) (LPS) are monitored through the control module.The unit is allowed to remain operational as long as the OPSand/or LPS have not been open for more than 2 minutes af-ter a compressor has started. After start-up, if the OPS and/orLPS are open for more than 2 minutes, the control moduleshuts down the compressor and places the unit in a lockoutcondition. The control module activates the fault indicationcircuit, and the unit service lamp is illuminated. The unitcannot be restarted until control power is manually cycled toOFF, then to ON.28