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This type of valve enables checking of the systempressure, or charging refrigerant without disturbingthe unit operation. An adaptor is necessary for thestandard serviceman’s gauge or hose connection to fitthe Schrader type valve.PRESSURE RELIEF VALVESSafety relief valves are required by many localconstruction codes. Various types of relief valves areavailable, and the system requirement may be dictated bythe local code requirement. Normally code requirementsspecify that the ultimate strength of the high side partsshall be a minimum of 5 times the discharge or rupturepressure of the relief valve, and that all condensing unitswith pressure vessels exceeding 3 cubic feet intervalvolume shall be protected by a pressure relief device.Discharge may be to the atmosphere, or it may be adischarge from the high pressure side of the system tothe low pressure side.A typical reseating type valve is shown in Figure 38.The valve opens at a preset pressure, and refrigerantis discharged until the pressure falls to the reseatingpoint.Some Copeland® brand compressors have reseatingtype pressure relief valves installed internally in thedischarge chamber which allow excessive pressuresto discharge to the suction chamber. A typical internaltype valve is shown in Figure 39.Rupture disc type relief devices have a thin disc which isdesigned to rupture at a given relief pressure, dischargingthe refrigerant to the atmosphere.FUSIBLE PLUGSA fusible plug is a safety device with a metal inserthaving a specified melting point. The allowable meltingpoint is defined by code, but normally it is the saturationtemperature of the refrigerant at a pressure no greaterthan 40% of the ultimate bursting pressure of therefrigerant containing vessel, or the critical temperatureof the refrigerant, whichever is lower .Fusible plugs are limited to units with pressure vesselsnot exceeding 3 cubic feet internal gross volume. Theyare used as a safety device in the event of fire, areresponsive to temperature only and will not protectagainst excessively high pressures.© 1967 Emerson Climate Technologies, Inc.All rights reserved.7-12
WATER REGULATING VALVESOn water cooled condensers, a modulating waterregulating valve is normally used to economize onwater usage and to control condensing pressureswithin reasonable limits. Water valves may be eitherpressure or temperature actuated and act to throttleflow as necessary.7-13© 1967 Emerson Climate Technologies, Inc.All rights reserved.
Page 3 and 4: Part IIREFRIGERATION SYSTEM COMPONE
Page 5 and 6: Section 4COMPRESSORSThe compressor
Page 7 and 8: CROSS-SECTIONAL VIEW OF COPELAMETIC
Page 9 and 10: When the piston starts down on the
Page 11 and 12: COMPRESSORS WITH UNLOADERSIn order
Page 13 and 14: flow by means of louvers is also an
Page 15 and 16: Figure No.20 shows parallel circuit
Page 17 and 18: and the total pressure existing in
Page 19 and 20: if the evaporator temperature is to
Page 21 and 22: In modern refrigeration practice, a
Page 23 and 24: CAPILLARY TUBE SELECTION R-22HIGH T
Page 25 and 26: CAPILLARY TUBE SELECTION R-12MEDIUM
Page 27 and 28: CAPILLARY TUBE SELECTION R-502LOW T
Page 29 and 30: multiple evaporators are used. On l
Page 31: which may be caused by pulsations i
Page 35 and 36: CONDENSER FAN CYCLING CONTROLIn ord
Page 37 and 38: 1. The continuous VA (volt-amperes)
Page 39 and 40: A. Continuous VA requirement2 Conta
Page 41 and 42: The desired pulley size or the resu
Page 43 and 44: un winding is wound with relatively
Page 45 and 46: TWO PHASE MOTORSTwo phase power is
Page 47 and 48: 1 = 1 + 1MFD total MFD1 MFD2For exa
Page 49 and 50: voltage torque, and star-delta star
Page 51 and 52: 10-6© 1967 Emerson Climate Technol
Page 53 and 54: Regular Copeland® brand motor prot
Page 55 and 56: contact prematurely due to shock or
Page 57 and 58: The effect of an open phase in the
Page 59 and 60: vulnerable to liquid damage such as
Page 61 and 62: REFRIGERATION GAUGESPressure gauges
Page 63 and 64: © 1967 Emerson Climate Technologie

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