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Questions and Answers
For small appliances, a standard vacuum pump ____.
What is not a small appliance?
HC refrigerant systems require permanent safety markings ____.
What is the pressure of a storage cylinder of R-410A, that is stored in a room where the temperature is 100 degrees Fahrenheit?
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The hydrocarbon refrigerant approved for retrofit into existing household refrigerators is ____.
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Recovery devices for use with small appliances must be capable of ____.
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Which maintenance practice should be performed on a regular basis?
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If a recovery cylinder is suspected to be contaminated, measure the ____.
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When you open a small appliance for maintenance, service, or repair, you must do one of the following:
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Which of the following is required by the EPA when attaching a gauge set?
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How can you speed refrigerant recovery from a frost-free refrigerator?
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New household refrigerators with a charge of less than 57 grams (2 ounces weight) can use any of the following refrigerants, EXCEPT.
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A passive system-dependent recovery process ____.
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A process stub is a ____.
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When a pungent odor is detected in the oil, this indicates ____.
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A passive recovery device can be used for a ____.
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Always look for oil contamination when recovering refrigerant because ____.
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When installing an access fitting, you must ensure ____.
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Which condition can cause excessive pressure on the high-side of a self-contained recovery device?
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What requires accessing both the high and low side of the system for refrigerant recovery when using a passive recovery process?
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Low- and high-side access valves can be installed instead of a single access valve to ____.
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For a system with an operating compressor and a restricted capillary tube, what is the minimum number of access valves needed and where would you place them?
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If you encounter a small appliance that is leaking, you must ____.
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New household refrigerators with a charge of less than 57 grams (2 ounces weight) can use any of the following refrigerants, EXCEPT:
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For a system with an operating compressor and a restricted capillary tube, what is the minimum number of access valves needed and where would you place them?
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Study Notes
Small Appliances and Recovery Devices
- A standard vacuum pump for small appliances can only recover refrigerant when used with an unpressurized container.
- An MVAC-like system holding three pounds of R-22 is not classified as a small appliance.
- HC refrigerant systems must have safety markings on or near evaporators, exposed refrigerant tubing, and the exterior of the unit.
Pressure and Refrigeration Standards
- The pressure in a storage cylinder of R-410A at 100°F is approximately 319 psig.
- Hydrocarbon refrigerants are not approved for retrofitting existing household refrigerators.
- Recovery devices must recover at least 90% of the refrigerant during compressor operation.
Maintenance and Safety Practices
- Regular maintenance includes changing vacuum pump oil, checking recovery equipment for leaks, and inspecting manifold hoses.
- Contaminated recovery cylinders are indicated by measuring refrigerant pressure.
- To recover refrigerant from small appliances, one must either recover 90% with the compressor running or evacuate to 4 inches of mercury vacuum.
Equipment and Recovery Techniques
- The gauge set must have self-sealing or manual hand valves to minimize refrigerant release.
- Accelerating refrigerant recovery in frost-free refrigerators can be achieved by turning on the defrost heater.
- Passive recovery devices can be used on small domestic refrigerators or walk-in freezers.
System Access and Contamination
- A process stub refers to a straight tubing piece sealed at the end, used for refrigerant servicing.
- A pungent odor in the oil typically indicates a compressor burnout.
- Always check for oil contamination when recovering refrigerant, as it may require system flushing.
High-Side Pressure and Recovery Access
- Excessive high-side pressure in a recovery device can result from a closed recovery tank valve, high tank temperature, or presence of non-condensable gases.
- Both high and low sides must be accessed for refrigerant recovery when the compressor is not running.
Recovery Valve Placement and Leak Management
- Using both high and low-side service ports during recovery speeds up the process and ensures full refrigerant recovery.
- For systems with a restricted capillary tube and an operating compressor, only one access valve is necessary on the high side.
- Repairs on leaking small appliances are not mandatory by law, but recommended due to the smaller refrigerant charge.
Modern Refrigerants Regulations
- Household refrigerators with less than 57 grams of refrigerant can use various refrigerants, but R-1235yf is an exception.
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Description
Test your knowledge on small appliances and recovery devices, including the standards for pressure and maintenance practices. This quiz covers essential safety regulations and the proper procedures for refrigerant recovery. Ideal for students and professionals in HVAC fields.
