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A LOOK AT SERVICE SAFETY

Compressor Motor and Component Information

27

IV.

Compressor  Motor  Starting 
Relays

A hermetic motor starting relay is an automatic
switching device to disconnect the motor start
capacitor and/or start winding after the motor has
reached running speed.

Never select a replacement relay solely by horse-
power or other generalized rating. Select the correct
relay from the Tecumseh Electrical Service Parts
Guide Book.

There are two types of motor starting relays used in
refrigeration and air conditioning applications: the
current responsive type and the potential (voltage)
responsive type.

A. Current Type Relay

When power is applied to a compressor motor, the
relay solenoid coil attracts the relay armature
upward causing bridging contact and stationary
contact to engage. This energizes the motor start
winding. When the compressor motor attains run-
ning speed, the motor main winding current is such
that the relay solenoid coil de-energizes allowing the
relay contacts to drop open thereby disconnecting
motor start winding.

The relay must be mounted in true vertical position
so armature and bridging contact will drop free
when relay solenoid is de-energized.

B. PTC Type Relay

Solid state technology has made available another
type of current sensitive relay—a PTC starting
switch. Certain ceramic materials have the unique
property of greatly increasing their resistance as they
heat up from current passing through them. A PTC
solid state starting device is placed in series with the
start winding and normally has a very low resistance.
Upon startup, as current starts to flow to the start
winding, the resistance rapidly rises to a very high
value thus reducing the start winding current to a
trickle and effectively taking that winding out of
operation.

Usage is generally limited to domestic refrigeration
and freezers. Because it takes 3 to 10 minutes to cool
down between operating cycles, it is not feasible for
short cycling commercial applications.

C. Potential Type Relay

Generally used with large commercial and air condi-
tioning compressors (capacitor start, capacitor run)
to 5 HP. Relay contacts are normally closed. The
relay coil is wired across the start winding and senses
voltage change. Starting winding voltage increases
with motor speed. As the voltage increases to the
specific pickup value, the armature pulls up, open-
ing the relay contacts, de-energizing the start wind-
ing capacitor. After switching, there is still sufficient
voltage induced in the start winding to keep the

Figure 3-17.

Current type relay.

Figure 3-18.

PTC type relay.

Содержание AEA4440YXA

Страница 1: ...Service Data Book Sold By American Refrigeration Supplies Inc Wholesale Distribution North America...

Страница 2: ...sonnel Only 2 III Terminal Venting and Electrocution 2 IV Refrigerants and Other Chemicals 4 V Compressor Removal 4 VI System Flushing Purging and Pressure Testing for Leaks 4 VII System Charging 5 VI...

Страница 3: ...n lead to serious burns or death When spray from ter minal venting is ignited this is called terminal vent ing with ignition See Figures 1 1 through 1 3 for detail B Terminal Venting and Electrocution...

Страница 4: ...up view of hermetic terminal showing individual terminal pins with power leads removed Figure 1 3 Close up view of hermetic terminal after it has vented Figure 1 4 Compressor with 1 protective termin...

Страница 5: ...ngs this can Cause a variety of injuries including burns and frostbite Cause a fire if a torch is used to discon nect tubing Expose the service person to toxic gas To avoid serious injury or death be...

Страница 6: ...rogen cylinder and release the pressure in the system before connecting a refrigerant container to the system The higher pressure gas in the system can explode the refrigerant container VII System Cha...

Страница 7: ...s a leak water can enter the refrigerant side of the system Water entering the refrigerant side can come in contact with live electrical connections in the compressor causing a short circuit or a path...

Страница 8: ...ter Utilizing System If you do not find any indication of a history of loss of charge without detection of a leak you still need to install a high pressure cut out which interrupts power to ALL leads...

Страница 9: ...E SAFETY 9 2 MODEL AND APPLICATION INFORMATION I Compressor Model Number Codes 10 II Condensing Unit Model Number Codes 11 III Serial Label Information 12 IV Basic Application Information for Hermetic...

Страница 10: ...cation 4 in the unit s model number Motor Starting T orque Normal High Normal High Normal Normal High Normal High Normal Normal Rating Pt 10 F 10 F 45 F 45 F 45 F 20 F 20 F 49 F 20 F 20 F 20 F Primary...

Страница 11: ...rcial Design N Advanced Commercial Design S Customer Special T Interconnect Compressor U Water Cooled Adv Commercial Design V Electrical Special Conduit Design W Water Cooled Unit X Interconnect Unit...

Страница 12: ...the same location Both describe the characteristics of the compressor The months are identified as identified in Table 2 1 Figure 2 3 Compressor serial label AH301FT 077 SE1490C V230 208Hz60 V200 Hz50...

Страница 13: ...SIDE DESIGN PRESSURE P S I MIN CIRCUIT AMPACITY F L A E A PH 60 HZ 50 HZ 58 8 8 8 1 0J00066332 2C234 9 AKA9446EXAXC 1 4 20 R 22 444 12 4 350 150 1 115 10F TO 45F 35W SER EM MOD 1P MADE IN USA 1 THERMA...

Страница 14: ...rigerant Use only the serial label refrigerant when charging the system Using a different refrigerant can lead to excess system pressure damage to the compressor and an explosion For example using R 5...

Страница 15: ...MOTOR AND COMPONENT INFORMATION I Single Phase Compressor Motor Types 16 II PSC Motor Starting 18 III Hermetic Compressor Thermal Protectors 19 IV Compressor Motor Starting Relays 27 V Selecting Capac...

Страница 16: ...ding as the motor comes up to design speed Three types of relays are used with this motor a current relay a wired in Positive Temperature Coefficient PTC relay or a module Positive Temperature Coeffic...

Страница 17: ...start capacitor or relay is necessary For addi tional starting torque a proper start assist kit may be added see Figure 3 6 Some start assist kits may include a wired in Positive Temperature Coeffici...

Страница 18: ...tion pressures must be equal and not more than 170 psig Refrigeration metering device cap tube or TX valve should equalize system pres sures within 3 minutes Unequal system pres sure may be caused by...

Страница 19: ...ressor housing quickly senses any unusual temperature rise or excess current draw The bi metal disc within the thermal protec tor see Figure 3 9 reacts to either excess tempera ture and or excess curr...

Страница 20: ...pplication Make no substitutions Will not protect motor if compressor is operated outside its evaporator temperature range Internal Line Break Thermal Protectors Currently used on all AH AB AV AG AW a...

Страница 21: ...arge gas temperatures Notes on the compressor electronic protection sys tem The compressor will not run if a jumper is placed across terminals S and S1 Terminals M1 and M2 are a normally closed switch...

Страница 22: ...t Compressor Sensors Compressor Power To Control Circuit Contactor Coil S1 C1 L1 L2 L3 R1 R2 R3 C2 S Table 3 3 AN Wiring on Typical System Model AN5590E F AN5610E F AN5612E F AN5614E F 8 TW 8 TW 6 TW...

Страница 23: ...t To M2 14 Min See Table 3 4 Use Copper Conductors Only 24 Volt Compressor Sensors Compressor Power To Control Circuit Control Line 230V 15AA1104C Electronic Protection Module S1 C1 L1 L2 L3 R1 R2 R3...

Страница 24: ...590G H AN5610G H AN5612G H AN5614G H 230 200 60 3 230 200 60 3 230 200 60 3 230 200 60 3 460 60 3 460 60 3 460 60 3 460 60 3 8 TW 8 TW 8 TW 6 TW 12 TW 12 TW 10 TW 10 TW 92 500 100 000 122 000 140 000...

Страница 25: ...25 E Small Terminal Block with Thermal Protector Figure 3 15 Small terminal block wiring on typical system with thermal protector T1 T2 T3 L1 L2 L3 Crankcase Heaters To Control Circuit Clear Tie Compr...

Страница 26: ...Tie Ground T1 M 1 T 1 M 2 S 1 S 2 T 2 To Protection Module Line Circuit Electronic Protection Module 15AA1104 See Table 3 6 Control Line 2 5A Max 24 115 230 V A C 3 PH Incoming Power Texas Instrument...

Страница 27: ...PTC Type Relay Solid state technology has made available another type of current sensitive relay a PTC starting switch Certain ceramic materials have the unique property of greatly increasing their r...

Страница 28: ...Motor Type Characteristics Current Relay RSIR and CSIR Sense starting current to main run windings Contacts normally open Contacts close and then release in less than 1 second as motor starts Must be...

Страница 29: ...rovided in Figures 3 20 and 3 21 Figure 3 20 Explanation of GE Potential Relay Code 3ARR3 A 3 Potential Relay Type Mounting Position C Number of Terminals and Bracket 5 Coil Group Continuous Voltage C...

Страница 30: ...nder cover See note on page 31 1 Face down 2 Face up 3 Face out horizontal numbers upside down 4 Face out 90 clockwise from number 3 position 5 Face out horizontal numbers right side up 6 Face out 90...

Страница 31: ...the relay is to be mounted It is of utmost importance that the relay be mounted in the required posi tion Mounting in any other position can change the relay s operating characteristics enough so tha...

Страница 32: ...Do not add excessive starting capacitance C Run Capacitors Since January 1979 capacitors provided by Tecum seh have contained non PCB oils or have been con structed using non PCB impregnated metalliz...

Страница 33: ...d may reduce start torque Capacitors in CSR motors should have 15 000 ohm 2 watt bleed resistor across terminals Capacitor rated voltage must be equal to or more than that speci ed Capacitor MFD shoul...

Страница 34: ...ve terminal cover While the protective ter minal cover may identify the terminal pins it is pri marily designed to reduce the risk of serious injury or death from electrocution or terminal venting wit...

Страница 35: ...ls Screw On Type Terminal Pins AN Terminals Figure 3 24 Current arrangements continued Common Run C S R T3 T1 T2 Start Run 1 Phase L3 3 Phase L2 3 Phase L1 3 Phase Common 1 Phase Start 1 Phase 24 Volt...

Страница 36: ...se or circuit breaker used to protect against short circuit and or ground fault of a unit utilizing a hermetic compressor shall be no more than the sum of 225 of the compressor Related Load Amps RLA a...

Страница 37: ...38 II Servicing or Troubleshooting Water Utilizing Systems Preventing Explosions 39 III Troubleshooting Chart 41 IV Identifying Compressor Electrical Problems 47 V Checking for Adequate Compressor Pum...

Страница 38: ...d follow the General Service Safety Precautions on pages 2 7 Before servicing THINK SAFETY Disconnect ALL electrical power before removing the protective terminal cover Never energize the system unles...

Страница 39: ...check to see if it has either a pressure relief valve or a high pressure cut out as previously described If the system does not have at least one of these DISCONNECT ALL ELECTRICAL POWER and look for...

Страница 40: ...the water inside the heat exchanger The entire system must be replaced See Replacing a Single Wall Water Utiliz ing System below If you do not find any indication of a history of loss of charge withou...

Страница 41: ...stions about returns under war ranty see Is your Compressor Eligible for Return Under Warranty on page 83 Complaint Possible Causes Response A Compressor will not start no hum 1 System component not f...

Страница 42: ...e accumulator will prevent liquid refrigerant from getting into the compressor 6 Internal mechanical trouble in compressor See Checking for Adequate Compressor Pumping on page 83 C Compressor starts b...

Страница 43: ...ical problems such as thermal protector or run capacitor not working properly See Identifying Compressor Electrical Problems on page 47 4 Discharge pressure too high If this is a water utilizing syste...

Страница 44: ...device a Refer to the OEM service information b Same as a c Same as a F Unit operates long or continuously 1 Undercharge of refrigerant If this is a water utilizing system see Servicing or Troubleshoo...

Страница 45: ...ms Preventing Explosions on page 39 Also refer to the OEM service information H Suction line frosted or sweating System problems such as a expansion valve passing excess refrigerant or is oversized b...

Страница 46: ...ak into refrigerant side of a water utilizing system See Servicing or Troubleshooting Water Utilizing Systems Preventing Explosions on page 39 Also refer to the OEM service information K System rattle...

Страница 47: ...nal cover Never energize the system unless the protective terminal cover is securely fastened and the compressor is properly connected to ground Never reset a breaker or replace a fuse without first c...

Страница 48: ...or short circuit in the motor windings or if the heater element of the thermal protector is open Use the procedure in Table 4 1 to check single and 3 phase motors Why use a megger or Hi Pot Tecumseh P...

Страница 49: ...d S C and R and S and R Add the resistance between C and S to the resistance between C and R This sum should equal the resistance found between S and R A small deviation in this comparison is acceptab...

Страница 50: ...rocedure for the compressor you are servicing For more information on Compressor motor types see Single Phase Compressor Motor Types on pages 16 17 Thermal protectors see Hermetic Compressor Thermal P...

Страница 51: ...m seh Electrical Service Parts Guide Book for informa tion on proper replacement parts or call Tecumseh Products Company at 1 800 211 3427 Thermal Protector Type Relay Type Capacitor Type Internal Ext...

Страница 52: ...hermal protector If there is no continuity then the thermal protector may be tripped Wait at least 5 minutes then check continuity again If there is still no continuity replace the thermal protector S...

Страница 53: ...arts Guide Book for informa tion on proper replacement parts or call Tecumseh Products Company at 1 800 211 3427 Thermal Protector Type Relay Type Capacitor Type Internal External Current Potential PT...

Страница 54: ...r any other device Step 3 Check Wired in PTC Relay Check the relay by measuring continuity between the pin holes where the R and S pins on the compressor are inserted If there is no continuity the rel...

Страница 55: ...al Service Parts Guide Book for informa tion on proper replacement parts or call Tecumseh Products Company at 1 800 211 3427 Thermal Protector Type Relay Type Capacitor Type Internal External Current...

Страница 56: ...tector Check the external thermal protector by measuring continuity between C and L on the starting and protector package If there is no continuity the thermal protector may be tripped Wait at least 5...

Страница 57: ...e Parts Guide Book for informa tion on proper replacement parts or call Tecumseh Products Company at 1 800 211 3427 Thermal Protector Type Relay Type Capacitor Type Internal External Current Potential...

Страница 58: ...een a Relay terminals 1 and S If there is continuity then the relay contacts are closed when they should be open Replace the current relay b Relay terminals 2 and M If there is no continuity replace t...

Страница 59: ...he compressor s thermal protector or sys tem components such as the thermostat control contac tor or high or low pressure cut out For more information on troubleshooting the thermal protector see Step...

Страница 60: ...rma tion on proper replacement parts or call Tecumseh Products Company at 1 800 211 3427 Thermal Protector Type Relay Type Capacitor Type Internal External Current Potential PTC Run Start Other auxili...

Страница 61: ...k Wiring Confirm that there is continuity between a The power input terminal on the thermal protector and 5 on relay b The protector common lead wire and C Step 5 Check Potential Relay Before checking...

Страница 62: ...ged operation on start cycle due to low voltage Determine if the line voltage is too low less than 90 of rated voltage Prolonged operation on start cycle due to incorrect relay Replace with correct re...

Страница 63: ...rvice Parts Guide Book for informa tion on proper replacement parts or call Tecumseh Products Company at 1 800 211 3427 Thermal Protector Type Relay Type Capacitor Type Internal External Current Poten...

Страница 64: ...rect relay Replace with correct relay Line voltage is too high or low greater than 110 or less than 90 of rated voltage Excessive short cycling Short cycling can be caused by problems with the compres...

Страница 65: ...is outside of this range then the start capacitor needs to be replaced As an alternative check the start capacitor by measuring conti nuity between relay terminals 1 and 4 a Rx1 scale If there is con...

Страница 66: ...ector If there is no continuity and Steps 1through 4 have been completed allowing the thermal protector sufficient time to reset replace the ther mal protector Step 6 Check Wiring Confirm that there i...

Страница 67: ...ernal External Current Potential PTC Run Start Figure 4 8 CSR compressor motor type with internal thermal protector without start winding protection potential relay and run and start capacitors Relay...

Страница 68: ...e internal thermal protector may be tripped Wait for it to cool off and close This may take more than an hour Check continuity again If there is replace the compressor Step 3 Check Run Capacitor CAUTI...

Страница 69: ...tion due to loose relay mounting Tighten relay mounting Use of incorrect run capacitor Replace with proper run capacitor Step 5 Check Start Capacitor CAUTION Using a 20 000 ohm resistor discharge the...

Страница 70: ...s thermal protector or sys tem components such as the thermostat control contac tor or high or low pressure cut out For more information on troubleshooting the thermal protector see Step 3 For trouble...

Страница 71: ...actual relay to locate the terminals If replacement parts are needed refer to the Tecum seh Electrical Service Parts Guide Book for informa tion on proper replacement parts Thermal Protector Type Rel...

Страница 72: ...place the thermal protector Step 4 Check Run Capacitor CAUTION Using a 20 000 ohm resistor discharge the capacitor before removing it from the system to avoid damage to measuring devices and risk of e...

Страница 73: ...leshooting If all above tests prove satisfactory and unit still fails to operate properly check for adequate compressor pumping as outlined in the procedure on page 83 Figure 4 11 PSC compressor motor...

Страница 74: ...pe Capacitor Type Internal External Current Potential PTC Run Start Figure 4 12 PSC compressor motor type with internal thermal protector without start winding protection and run capacitor Compressor...

Страница 75: ...nuity replace the compressor Step 3 Check Run Capacitor CAUTION Using a 20 000 ohm resistor discharge the capaci tor before removing it from the system to avoid damage to mea suring devices and risk o...

Страница 76: ...informa tion on proper replacement parts or call Tecumseh Products Company at 1 800 211 3427 Thermal Protector Type Relay Type Capacitor Type Internal External Current Potential PTC Run Start wired Fi...

Страница 77: ...r terminals a Rx1 scale If there is continuity then the run capacitor is shorted and needs to be replaced b Rx100 000 scale If there is no needle deflection on an analog meter or if a digital meter in...

Страница 78: ...n on proper replacement parts or call Tecumseh Products Company at 1 800 211 3427 Thermal Protector Type Relay Type Capacitor Type Internal External Current Potential PTC Run Start module plug in Figu...

Страница 79: ...em Use a capacitance meter to check capacitor Capacitance should be 10 of the marked capacitor value As an alternative check the run capacitor by measuring conti nuity across the capacitor terminals C...

Страница 80: ...compressor are inserted If there is no continuity the relay may be open Wait 3 minutes then check continuity again If there is still no continuity replace the protector package Step 6 Continue Trouble...

Страница 81: ...to the Tecumseh Electrical Service Parts Guide Book for information on proper replacement parts or call Tecumseh Products Company at 1 800 211 3427 Figure 4 16 3 phase motor with solid state protecti...

Страница 82: ...that the control thermo stat and contactor are working properly Step 2 Allow Thermal Protector to Reset When servicing 3 phase motors be sure to allow time for the internal thermal protector to reset...

Страница 83: ...s down and exam ines a representative sample of compressors returned by authorized wholesalers and notes the reason for failure In the field it can be determined if a compressor is eligible for return...

Страница 84: ...84 Chapter 4...

Страница 85: ...ube Connections 86 II Refrigerant Line Sizes 88 III Refrigerant Line Pressure Drops 93 IV Refrigerant Line Velocities 98 V Service Valves 103 VI Processing the System 103 VII System Cleanup and Compre...

Страница 86: ...ation of compressor connections can usually be accomplished without difficulty however occa sionally some question arises concerning oil cooler tubes and process tubes Oil cooler tubes are found only...

Страница 87: ...lation and Replacement Information 87 Figure 5 1 Standard discharge tubing arrangements continued AK Air Conditioning Discharge Tube Discharge Tube Discharge Tube Discharge Tube Discharge Tube Dischar...

Страница 88: ...l trapping in the evaporator If because of the spillover the return gas is wet at the compressor a suction line accumulator should be installed adjacent to the compressor On systems with evaporators b...

Страница 89: ...1 8 1 3 8 1 1 8 1 1 8 1 2 36000 3 1 8 2 1 8 1 5 8 1 3 8 1 1 8 1 2 48000 3 5 8 2 5 8 2 1 8 1 5 8 1 3 8 1 2 60000 3 5 8 2 5 8 2 5 8 1 5 8 1 3 8 1 2 72000 4 1 8 3 1 8 2 5 8 2 1 8 1 5 8 1 2 Table 5 2 R 22...

Страница 90: ...traps are not required Horizontal suction lines are sized larger to reduce pressure drop Suction line lengths in excess of 100 are not recommended On heat pump systems the lines serving as both a dis...

Страница 91: ...bles 5 4 and 5 5 show recommended suction line sizes for installations where that line is horizontal or down flow In the event the suction line is up flow use one standard size smaller EXAMPLE Where a...

Страница 92: ...3 4 5 8 1 2 1 2 1 4 4800 1 1 8 7 8 3 4 5 8 1 2 1 4 6000 1 1 8 7 8 3 4 5 8 1 2 1 4 7200 1 3 8 1 1 8 7 8 3 4 5 8 1 4 8400 1 3 8 1 1 8 7 8 3 4 5 8 3 8 9600 1 5 8 1 1 8 7 8 3 4 5 8 3 8 10800 1 5 8 1 3 8 1...

Страница 93: ...e Drop 1 0 p s i 100 ft At 120 F Condenser At 100 F Condenser At 80 F Condenser 6 1 8 5 1 8 4 1 8 3 5 8 3 1 8 2 1 8 1 5 8 1 1 8 7 8 3 4 5 8 1 2 3 8 6 0 F E v a p o r a t o r T e m p e r a t u r e 4 0...

Страница 94: ...r a t u r e 4 0 F 1 3 8 O D T y p e L C o p p e r T u b i n g 3 1 8 2 1 8 Tons of Refrigeration Pressure Drop In Lbs Per Sq In Per 100 Ft EXAMPLE 5 5 Tons at 40 F Evap 85 F Cond 2 5 8 Suction Line Pre...

Страница 95: ...enser At 100 F Condenser At 120 F Condenser 7 1 8 6 1 8 5 1 8 4 1 8 3 5 8 3 1 8 2 5 8 2 1 8 1 5 8 1 3 8 1 1 8 7 8 3 4 1 2 3 8 5 8 O D T y p e L C o p p e r T u b i n g 6 0 F E v a p o r a t o r T e m...

Страница 96: ...g 5 1 8 4 1 8 3 5 8 3 1 8 2 5 8 2 1 8 1 5 8 1 3 8 1 1 8 7 8 3 4 5 8 1 2 3 8 5 0 C E v a p o r a t o r T e m p e r a t u r e s 4 0 C 2 0 C 0 C 3 0 C 1 0 C 1 0 C D i s c h a r g e L i n e s L i n e s L...

Страница 97: ...p o r a t o r T e m p e r a t u r e 4 0 F 2 0 F 2 0 F 4 0 F D i s c h a r g e L i n e s L i q u i d L i n e s 0 F 5 1 8 4 1 8 3 5 8 3 1 8 2 5 8 2 1 8 1 5 8 1 3 8 1 1 8 7 8 3 4 5 8 1 2 3 8 Pressure Dro...

Страница 98: ...F Condenser EXAMPLE 5 5 Tons at 40 F Evap 85 F Cond 3 1 8 Suction Line Velocity 1916 ft min 3 4 Liquid Line Velocity 94 ft min At 100 F Condenser At 120 F Condenser 6 1 8 6 0 F E v a p o r a t o r T...

Страница 99: ...enser At 100 F Condenser At 120 F Condenser 5 1 8 4 1 8 6 0 F E v a p o r a t o r T e m p e r a t u r e D i s c h a r g e l i n e s 8 0 F C o n d e n s e r 4 0 F 2 0 F 2 0 F 4 0 F L i q u i d L i n e...

Страница 100: ...enser At 100 F Condenser At 120 F Condenser 6 1 8 1 5 8 1 3 8 1 1 8 7 8 3 4 5 8 1 2 3 8 5 1 8 4 1 8 3 5 8 3 1 8 2 5 8 2 1 8 6 0 F E v a p o r a t o r T e m p e r a t u r e 4 0 F 2 0 F 0 F 2 0 F 4 0 F...

Страница 101: ...denser At 50 C Condenser 6 1 8 O D T y p e L C o p p e r T u b i n g 5 1 8 4 1 8 3 5 8 3 1 8 2 5 8 7 8 3 4 5 8 3 8 1 2 2 1 8 1 5 8 1 1 8 1 3 8 5 0 C E v a p o r a t o r T e m p e r a t u r e s 4 0 C 3...

Страница 102: ...uid Line Velocity 0 37 m s NOTE Liquid line determined at 20 C evap and 30 C cond Discharge lines at 20 C evap Other conditions do not appreciably change result Net refrigeration for HFC 134a includes...

Страница 103: ...nd scale forming inside the tubes it is good practice to flow dry nitro gen through the tubing during the soldering operations A light flow of about 1 4 cubic feet per minute is sufficient 3 Install a...

Страница 104: ...it does not mean that a fire actu ally occurs inside a hermetic compressor Even small amounts of contamination must be removed from the system to avoid damaging the replacement compressor Therefore it...

Страница 105: ...of the accumulator and the compressor In the case of Compressor Housing Contami nation the filter drier should be installed between the compressor and the suction line accumulator Rubber refrigeratio...

Страница 106: ...l be mea sured Change the suction filter drier and the liquid line filter drier whenever the pressure drop approaches or exceeds that allowed for temporary operation during cleanup see Table 5 4 Keep...

Страница 107: ...s A reading of less than 0 05 acid number is an indication that the sys tem is free of acid A reading of higher than 0 05 means continued cleaning is required Return to B2 on page 105 G Monitor the Sy...

Страница 108: ...zing systems that have single wall heat exchangers may present a risk of explosion Such systems may include water source heat pump air conditioning sys tems and water cooling systems such as icemakers...

Страница 109: ...to the Compressor During Shutdown 110 II Crankcase Heaters 113 III Starting a System with Liquid Refrigerant in the Compressor 114 IV Control of Liquid Refrigerant Floodback to the Compressor During...

Страница 110: ...Products Company A five ton split air conditioning system was used with a four inch sight glass installed in the compressor housing The condensing unit and evaporator sec tion were connected by appro...

Страница 111: ...3 Five seconds after start up violent foaming action lls sight glass as refrigerant boils away taking oil charge with it Figure 6 4 More than 60 seconds after start up oil level is well below normal...

Страница 112: ...s while operating This con dition can be controlled by the application of a suc tion line accumulator Crankcase heat does nothing to prevent liquid floodback and an accumulator does nothing to prevent...

Страница 113: ...m tempera ture of 80 F The immersion type heater is factory assembled and is presently used with AB AW AG AV and AN compressors It is self regulating and energy effi cient In the run capacitance off c...

Страница 114: ...ne to two seconds then wait 1 to 2 minutes After 3 or 4 jogs apply power contin uously WARNING Jogging a compressor that has an electrical problem can increase the likeli hood of terminal venting To r...

Страница 115: ...t in an accumulation of the refrigerant under the oil see Figure 6 10 Thus when the compressor is started the first liquid to be pumped to the bearings will probably be refrigerant not oil Even if thi...

Страница 116: ...han 60 seconds after start up oil level is well below normal operating levels a condition that is an important factor in compressor bearing wear Figure 6 11 Five seconds after start up violent foaming...

Страница 117: ...cumulation in the compressor can also be caused by liquid migration to the compressor during periods of shutdown This condition can be controlled by the application of a crankcase heater A suction lin...

Страница 118: ...temperature and capacity in tons of refrigeration These factors were considered in the design and test ing of the accumulator If on older systems the system refrigerant charge is not known consider th...

Страница 119: ...ere The IPR valve may also open to relieve hydraulic pressures in the event of slugging This is apt to occur on startup if refrigerant has been allowed to migrate to the compressor crankcase It is a c...

Страница 120: ...120 Chapter 6...

Страница 121: ...LOOK AT SERVICE SAFETY Appendix 121 APPENDIX I The Basic Refrigeration Cycle 122 II Example of a Tecumseh Hermetic Compressor 124 III Capillary Tube Sizing 126 IV Approved Hermetic Compressor Oils 12...

Страница 122: ...ential across the expansion device or in the case of a thermal expansion valve by the degree of superheat of the suction gas Thus the thermal expansion valve shown requires a sensor bulb located at th...

Страница 123: ...Receiver Tank Condenser Fan T X Valve Sensor Bulb Expansion Valve or Capillary Tube Strainer Drier Low Pressure Side Low Pressure Gas High Pressure Gas Low Pressure Liquid High Pressure Liquid Evapor...

Страница 124: ...frigerant gas surrounds the compressor crankcase and motor as it is drawn through the compressor housing and into the cylinder s through the suction muffler and suction valves As the gas is pressured...

Страница 125: ...A LOOK AT SERVICE SAFETY Appendix 125 Figure A 2 Internal view of typical air conditioning compressor...

Страница 126: ...Capacity BTU Hr Condenser Type Normal Evaporating Temperature 10 TO 5 F 5 TO 20 F 200 300 Static or Fan 16 026 10 026 300 400 Static or fan 12 026 12 031 400 700 Static 12 031 12 036 Fan 10 031 10 036...

Страница 127: ...12 042 1800 2500 Fan 12 042 12 049 8 049 2500 3500 Fan 10 042 10 049 3500 4000 Fan 12 049 10 054 4000 5000 Fan 10 054 10 059 5000 6000 Fan 12 059 12 064 6000 7000 Fan 10 059 10 064 12 070 7000 10000...

Страница 128: ...ding per circuit becomes 6100 BTU Hr Use 40 x 049 or 75 x 054 if the intention is to feed each circuit with a separate cap tube Fewer number of cap tubes are optional of course Assuming a 1 2 OD tube...

Страница 129: ...in accordance with good engineering practice Some system designs containing unusual evapora tors and or extensive interconnected piping may require additional oil However since excess oil can also dam...

Страница 130: ...cal Zerol 300 Soltex SA56 Petrobras CP32RHS Napthenic Paraf nic Witco LP200 Penreco Sontex 200LT A LT Paraf nic Total A68 Polyol Ester Emkarate RL32S Mobil EAL Arctic 32 22 Cognis ProEco 32ML Castrol...

Страница 131: ...arge oz AB all 32 AEA 1360 80 10 16 AE all others 10 AG 65 AHA2466 80 38 AH all others 45 AJ 26 AK 17 AN 140 AV 54 AWA 2XXX 7XXX 9XXX 38 AWE all others 32 AWF all others 32 AWG J all others 38 AZA 320...

Страница 132: ...132 Appendix...

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