Sealed System Information
HFC-134a REFRIGERANT SERVICE INFORMATION
The 600 Series sealed systems contain HFC-134a refrigerant. This section provides general rules for working with 134a, and explains procedures to be followed while servicing the sealed system. This is followed by diagrams which illustrate sealed system operation, then model-specific refrigerant flow diagrams.
CAUTION
134a refrigerant requires Synthetic Ester oil in the compressor, and does not tolerate contamination from other refrigerants, moisture, petroleum-based lubricants, silicone lubricants, cleaning compounds, rust inhibitors, leak detection dyes, or any other type of additive.
General Rules for Working with 134a Refrigerant
- Use equipment dedicated to 134a sealed system service only.
- Use only 134a refrigerant for back-flushing and sweep charging.
- Always replace the filter-drier when servicing the sealed system.
- The filter-drier must be cut from the sealed system. Never un-braze the drier as the heat will drive moisture back into the sealed system.
- Do not leave sealed system nor replacement compressor open to the atmosphere for more than 10 minutes.
- When the rubber plugs are pulled from the service compressor, a release of pressure should be heard. If no release of pressure is heard, do not use the compressor.
- Use ONLY virgin 134a refrigerant when recharging the sealed system.
600 SERIES SEALED SYSTEM REPAIR PROCEDURES
| Problem | Service Procedures |
|---|---|
| Non-Operating, Inefficient, Noisy Compressor |
NOTE: To check for a non-operating compressor, a hard start kit can be used. |
| High Side leak |
|
| Low Side Leak |
|
| Contaminated Sealed System | Examples:
Procedures:
|
| Restriction |
NOTE: If restriction is due to sealed system being contaminated, see Contaminated Sealed System above. |
| Overcharge |
|
SEALED SYSTEM OPERATION
The following six diagrams illustrate a basic sealed system. The components are listed in order of refrigerant flow, with an explanation of their fundamental role as part of a sealed system. NOTE: These illustrations do not represent any specific 600 Series sealed system.
Compressor (Figure 4-1)
The compressor creates a high side and low side pressure difference in the sealed system by compressing the refrigerant gas, thus raising the pressure and temperature. The compressor pushes this high-pressure/high-heat gas through the door gasket seat heater loop to prevent sweating (on most units the gas also travels through drain pan heater tubing to help evaporate water in the drain pan). The high-pressure/high-heat gas then travels to the condenser.
Diagram Description (Figure 4-1. Compressor): Illustrates a compressor unit connected to a door gasket seat heater loop and drain pan heater tubing. The output port of the compressor is shown leading towards the condenser.
Condenser (Figure 4-2)
The high-pressure/high-heat gas travels through the condenser, where the heat is dissipated by cooler air being drawn over the condenser tubing by the condenser fan. This changes the gas into a high-pressure/warm liquid that then enters the high-side filter-drier.
Diagram Description (Figure 4-2. Condenser): Depicts the condenser unit receiving high-pressure gas. Airflow is implied to facilitate heat dissipation, converting the gas into a high-pressure liquid.
High-Side Filter-Drier (Figure 4-3)
The high-pressure/warm liquid travels through the high-side filter-drier, which removes moisture from the refrigerant before it enters the capillary tube.
Diagram Description (Figure 4-3. High-Side Filter-Drier): Shows high-pressure liquid entering the filter-drier. The component is depicted as a cylindrical unit, with the output port leading towards the capillary tube.
Capillary Tube (Part of Heat Exchanger) (Figure 4-4)
The high-pressure/warm liquid refrigerant travels through the long skinny capillary tube which is attached to the suction line. (These two tubes soldered together create the heat exchanger.) As the high-pressure/warm liquid refrigerant travels through the capillary tube it gives up heat to the cool refrigerant gas traveling through the suction line and the pressure drops, so it is a low-pressure/cool liquid before it enters the evaporator.
Diagram Description (Figure 4-4. Capillary Tube (Part of Heat Exchanger)): Illustrates a capillary tube running parallel and attached to a suction line, forming a heat exchanger. The diagram shows the flow of high-pressure liquid into the capillary tube and cool gas through the suction line.
Evaporator (Figure 4-5)
As the low-pressure/cool liquid refrigerant enters the evaporator, it vaporizes. This is caused by a dramatic pressure change which occurs when the refrigerant enters the larger diameter evaporator tubing from the smaller diameter capillary tubing. This vapor travels through the evaporator absorbing heat from the compartment, gradually converting it to a cool gas. This cool gas then enters the suction line.
Diagram Description (Figure 4-5. Evaporator): Shows the evaporator coil, typically a grid of tubes, receiving cool refrigerant. The diagram indicates the refrigerant vaporizing and absorbing heat from the compartment before exiting as cool gas into the suction line.
Suction Line (& Heat Exchanger) (Figure 4-6)
The cool gas travels through the suction line which is attached to the capillary tube. (As mentioned earlier, these two tubes soldered together create the heat exchanger.) As this cool refrigerant gas travels through the suction line it absorbs heat from the warm liquid refrigerant traveling through the capillary tube, making it a luke warm gas. The lukewarm refrigerant gas returns to the compressor where the process begins again.
Diagram Description (Figure 4-6. Suction Line (Part of Heat Exchanger)): Depicts the suction line carrying cool gas from the evaporator. This line is shown attached to the capillary tube, forming the heat exchanger. The diagram illustrates the heat transfer from the capillary tube to the suction line.
Refrigerant Flow Diagrams
The following diagrams illustrate refrigerant flow for specific Sub-Zero 600 Series models.
Figure 4-7. Models 601R, 601RG Refrigerant Flow
This diagram shows a single-compressor system for refrigerator models 601R and 601RG. It includes a compressor, condenser, high-side filter drier, refrigerator evaporator, and heat exchanger. A drain pan heater is also indicated.
Figure 4-8. Model 601F Refrigerant Flow
This diagram illustrates a single-compressor system for the freezer model 601F. It features a compressor, condenser, high-side filter drier, freezer evaporator, and heat exchanger. A drain pan heater is also shown.
Figure 4-9. Models 611, 611G, 650, 650G Refrigerant Flow
This diagram depicts a dual-system configuration for models 611, 611G, 650, and 650G. It includes a freezer compressor and a refrigerator compressor, a dual condenser, a freezer drier, a refrigerator drier, a freezer evaporator, a refrigerator evaporator, a freezer heat exchanger, a refrigerator heat exchanger, a freezer heater loop, a refrigerator heater loop, and a drain pan heater.
Figure 4-10. Models 632, 642, 680, 690 Refrigerant Flow
This diagram shows a dual-system setup for models 632, 642, 680, and 690. It includes a freezer compressor and a refrigerator compressor, a dual condenser, a freezer drier, a refrigerator drier, a freezer evaporator, a refrigerator evaporator, a heat exchanger for both freezer and refrigerator sections, a freezer heater loop, a refrigerator heater loop, and a drain pan heater.
