Sealed System Basics
Technical Sheet Always refer to the technical data sheet or Service Manual for the design specifications of the refrigerat...
The Main Components <ul><li>Compressor  / considered the heart of the sealed system and is responsible for circulating ref...
Variable Speed vs. Single Speed Compressor <ul><li>The EF42 and 48 both utilize variable speed 170 volt DC compressors.  T...
Single Speed Compressor <ul><li>The EF36 refrigerators all use a single speed, 120 vac compressor </li></ul><ul><li>Breaki...
Normal Operating Flow Compressor Condenser (Heat Exchanger) Refrigerant Flow High Side Low Side Vapor Evaporator Condenser...
Low Side  (Evaporator)  Liquid level varies but  normally last couple of  passes of condenser is  filled with liquid when ...
Internal Factors Affecting System Performance <ul><li>Low Charge </li></ul><ul><li>High Side Leak </li></ul><ul><li>Low Si...
Leak: Showing Low Charge Cooler Condenser Evaporator Low liquid level Low Current Draw (Wattage) Evaporator partially fros...
High Side Leak / No Refrigerant  Low Watts No frost on evaporator Warm Evaporator Cool Condenser Warm Evaporator Liquid Le...
Low Side Leak  Air In System Condenser Evaporator High Current Draw (Wattage) No frost on evaporator No liquid
Complete Cap Tube Restriction Low Current Draw (Wattage) No Frost   Condenser full of liquid Condenser Evaporator X
Condenser Evaporator Low Current  Draw Liquid level low or  non existent Condenser Evaporator Low Current  Little or no li...
Overcharged System Condenser Evaporator High Current Draw (Wattage) Suction Line frosted all the way back to compressor Hi...
Restricted Condenser Air Flow Very Hot Condenser Very Little Frost Pattern Very Little Frost Pattern Condenser Evaporator ...
Amps -
Abnormal Heat Loads   <ul><li>Overloading unit with fresh food </li></ul><ul><li>Doors left open </li></ul><ul><li>Interio...
Amps -
Before Entering A Sealed System <ul><li>Air flow- </li></ul><ul><li>Are both the condenser and evaporator fans working? </...
Before Entering A Sealed System: <ul><li>Condenser </li></ul><ul><li>Is the condenser clean? </li></ul><ul><li>Is the cond...
Before Entering A Sealed System <ul><li>Ambient Affect </li></ul><ul><li>Is the refrigerator installed in an area where th...
Before Entering A Sealed System <ul><li>Once all external causes for the reduction in cooling capacity are eliminated, a c...
Before Entering A Sealed System <ul><li>Check compressor current draw.  Whether amp or watt, current draw should match the...
Before Entering A Sealed System <ul><li>Feel the top of the compressor (compressor dome).  </li></ul><ul><ul><li>If too ho...
<ul><li>Compressor may not be pumping efficiently </li></ul><ul><li>Sealed system may have a low charge </li></ul><ul><li>...
<ul><li>The system has a restriction and with a new drier installed, it is likely at the capillary inlet to the evaporator...
<ul><li>If you open a system in order to repair a leak or replace a compressor you must always install a new drier </li></...
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  • Sealedsystemtest

    1. 1. Sealed System Basics
    2. 2. Technical Sheet Always refer to the technical data sheet or Service Manual for the design specifications of the refrigerator under test Example
    3. 3. The Main Components <ul><li>Compressor / considered the heart of the sealed system and is responsible for circulating refrigerant throughout entire sealed system </li></ul><ul><li>Condenser / similar to a small radiator this heat exchanger helps dissipate heat picked up by the refrigerant and liquid compression process </li></ul><ul><li>Evaporator / protected and generally made from very conductive aluminum, the freezer evaporator is the cooling element of the refrigeration system </li></ul><ul><li>Drier / the drier is placed within the sealed system and is used to accumulate moisture and prevent it from circulating throughout the sealed system. Moisture will freeze upon entering evaporator and could lead to a restriction </li></ul><ul><li>Capillary Tube / the capillary tube is used as a metering device to control refrigerant flow and to aid the flash process </li></ul>
    4. 4. Variable Speed vs. Single Speed Compressor <ul><li>The EF42 and 48 both utilize variable speed 170 volt DC compressors. These units run nearly 90% of the time and will change speed based upon freezer cooling demand and ambient temperature. </li></ul><ul><li>Operating between 1600 and 4500 RPM, the primary advantage of the variable speed system is its ability to maintain very steady temperatures without the usual swings of a normally cycled compressor. </li></ul><ul><li>Eliminating the stress of start up, reliability has also been well above normal. </li></ul>
    5. 5. Single Speed Compressor <ul><li>The EF36 refrigerators all use a single speed, 120 vac compressor </li></ul><ul><li>Breaking tradition with other contemporary refrigerators: compressor cycling is based upon freezer temperatures rather than refrigerator temperatures </li></ul><ul><li>Driven by a computer board and a standard start relay: the compressor is either on 100% or off. There is no variable speed </li></ul>
    6. 6. Normal Operating Flow Compressor Condenser (Heat Exchanger) Refrigerant Flow High Side Low Side Vapor Evaporator Condenser Fan Airflow Heater
    7. 7. Low Side (Evaporator) Liquid level varies but normally last couple of passes of condenser is filled with liquid when running Low Side (Evaporator) Running Amperage approximately 1 amp (Ranges from .5 to 1.5 amps) depending on Compressor BTU rating and ambient conditions Normal Operating Cycle High Side Pressure (Condenser) Approximately 120 to 130 PSI Liquid level varies but normally the last few passes of the condenser contain liquid refrigerant Low Side Pressure (Evaporator) Approximately -2 PSI (Variable Speed Ranges Between -2 inches of vacuum and 5-7 lb PSI Evaporator frosted from top to bottom
    8. 8. Internal Factors Affecting System Performance <ul><li>Low Charge </li></ul><ul><li>High Side Leak </li></ul><ul><li>Low Side Leak </li></ul><ul><li>Factory Undercharge – Very rare </li></ul><ul><li>Overcharge </li></ul><ul><li>Restrictions </li></ul><ul><li>Partial </li></ul><ul><li>Full </li></ul><ul><li>Floating </li></ul><ul><li>Inefficient Compressor - Very Rare </li></ul><ul><li>Has the System been entered? If so, all the above factors should be considered . </li></ul>
    9. 9. Leak: Showing Low Charge Cooler Condenser Evaporator Low liquid level Low Current Draw (Wattage) Evaporator partially frosted or possibly an ice ball on first pass or two of evaporator coil
    10. 10. High Side Leak / No Refrigerant Low Watts No frost on evaporator Warm Evaporator Cool Condenser Warm Evaporator Liquid Level- None Low Current Draw (Wattage)
    11. 11. Low Side Leak Air In System Condenser Evaporator High Current Draw (Wattage) No frost on evaporator No liquid
    12. 12. Complete Cap Tube Restriction Low Current Draw (Wattage) No Frost Condenser full of liquid Condenser Evaporator X
    13. 13. Condenser Evaporator Low Current Draw Liquid level low or non existent Condenser Evaporator Low Current Little or no liquid in the condenser Low Amperage Draw (Wattage) Partial or no frost on the evaporator Inefficient Compressor
    14. 14. Overcharged System Condenser Evaporator High Current Draw (Wattage) Suction Line frosted all the way back to compressor High than normal liquid level
    15. 15. Restricted Condenser Air Flow Very Hot Condenser Very Little Frost Pattern Very Little Frost Pattern Condenser Evaporator High Current Draw (Wattage) Condenser Evaporator
    16. 16. Amps -
    17. 17. Abnormal Heat Loads <ul><li>Overloading unit with fresh food </li></ul><ul><li>Doors left open </li></ul><ul><li>Interior lights remaining on </li></ul><ul><li>Defrost system failure – heater stays on </li></ul><ul><li>Obstructed condenser </li></ul><ul><li>High room ambient </li></ul>
    18. 18. Amps -
    19. 19. Before Entering A Sealed System <ul><li>Air flow- </li></ul><ul><li>Are both the condenser and evaporator fans working? </li></ul><ul><li>Is the damper operational? </li></ul><ul><li>Is the return air duct from the fresh food compartment to the freezer free of obstructions? </li></ul><ul><li>Evaporator- </li></ul><ul><li>Is the evaporator plugged with ice (defrost problems)? </li></ul><ul><li>Is there a full frost pattern? </li></ul><ul><li>Does the suction line going back to the compressor feel cool or warm to the touch? </li></ul><ul><li>Is the suction line frozen? </li></ul>
    20. 20. Before Entering A Sealed System: <ul><li>Condenser </li></ul><ul><li>Is the condenser clean? </li></ul><ul><li>Is the condenser fan running efficiently? </li></ul><ul><li>Is there enough room around the refrigerator to allow air flow (especially critical with static and warm wall condensers)? </li></ul><ul><li>Does the condenser feel cool or warm to the touch? </li></ul><ul><li>Compressor- </li></ul><ul><li>Is the compressor running or has the compressor kicked off on overload? </li></ul><ul><li>Is the compressor start system or power supply functioning properly? </li></ul>
    21. 21. Before Entering A Sealed System <ul><li>Ambient Affect </li></ul><ul><li>Is the refrigerator installed in an area where the temperature often exceeds 95ºF?/ The result… </li></ul><ul><li>Is the refrigerator installed in an area where the temperature drops below 55ºF? / The result… </li></ul><ul><li>Is the refrigerator installed next to a range? </li></ul><ul><li>The answers to these questions will often pinpoint a condition that could mimic a sealed system problem. </li></ul>
    22. 22. Before Entering A Sealed System <ul><li>Once all external causes for the reduction in cooling capacity are eliminated, a closer look at the system is in order. Follow these steps to verify a system problem: </li></ul><ul><li>Remove the back cover or lift the machine compartment cover and feel the compressor discharge line. </li></ul><ul><ul><li>A very hot line indicates that the compressor is operating under extreme duress (high ambient, overcharged, very high heat load). </li></ul></ul><ul><ul><li>A cool line indicates that the compressor is not doing much work (leak, very low ambient, evaporator plugged with ice). </li></ul></ul>
    23. 23. Before Entering A Sealed System <ul><li>Check compressor current draw. Whether amp or watt, current draw should match the conditions that you encountered in first two steps. </li></ul><ul><ul><li>Low current draw could indicate a loss of refrigerant, an inefficient compressor, a restriction (cap tube plugged), or lack of air movement through the evaporator </li></ul></ul><ul><ul><li>High current draw could point to a tight compressor rotor, high ambient, high heat load (such as a light on in the refrigerator), non- condensables in the system, lack of air movement through condenser or an overcharge </li></ul></ul>
    24. 24. Before Entering A Sealed System <ul><li>Feel the top of the compressor (compressor dome). </li></ul><ul><ul><li>If too hot to touch but there is no cooling occurring, suspect air (non- condensable) has entered into the system. </li></ul></ul><ul><ul><li>If running but cool to the touch, compressor is not doing very much work and the system may be out of refrigerant or have evaporator air flow problems. </li></ul></ul><ul><li>If these further checks indicate that the problem is indeed with the sealed system, tap into the system. </li></ul>
    25. 25. <ul><li>Compressor may not be pumping efficiently </li></ul><ul><li>Sealed system may have a low charge </li></ul><ul><li>Tap sealed system and check charge. If low, recharge to recommended level and immediately check for leaks with leak detector </li></ul><ul><li>Once leak is found, repair or replace component, install new dryer, vacuum and recharge system to recommended level and seal off system. </li></ul>Sealed System Procedures System Observation: Partial Frost Pattern
    26. 26. <ul><li>The system has a restriction and with a new drier installed, it is likely at the capillary inlet to the evaporator or… </li></ul><ul><li>The system has an inefficient compressor </li></ul><ul><ul><li>This is very rare but is possible </li></ul></ul><ul><ul><li>Stop and immediately restart the compressor If it trips on overload it indicates a restriction </li></ul></ul><ul><ul><li>Repair restriction or replace compressor </li></ul></ul><ul><li>Complete the service call </li></ul>Sealed System Procedures After installing a new dryer and vacuuming the system, if the original partial frost pattern reoccurs:
    27. 27. <ul><li>If you open a system in order to repair a leak or replace a compressor you must always install a new drier </li></ul><ul><li>If you re-use the original dryer you will not protect the system from moisture damage </li></ul>Drier Procedures

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