Questions and Answers
When a new system has been assembled, what is the first thing to do?
Pressurize the system with an inert gas & leak check.
After installation of a field-piped R-410A split heat pump, what should the unit first be?
Pressurized with nitrogen then leak checked.
The EPA regulations require that any appliances containing more than 50 pounds of refrigerant must be repaired when the leak rate exceeds _________ of the charge per year.
15%
R-410A requires recovery tanks rated for at least?
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After refrigerant liquid has been recovered from a system, what happens to any remaining vapor?
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What must be done before recovering R-22 refrigerant from a unit if your recovery/recycling machine has R-502 refrigerant in it?
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In a refrigeration system with a TXV, what component directly follows the condenser?
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When charging an R-410A system that uses a water-cooled condenser, you must first charge with vapor to a pressure of at least ________.
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Recovered refrigerant may contain what?
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What must be done before your recovery unit can be used to recover R-410A if it has R-22 refrigerant in it?
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To recover liquid refrigerant, you must connect one hose to the?
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The proper charging method for blended refrigerants (400 Series) is to remove the charge from the cylinder as a?
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Before using a recovery unit to remove a charge, what steps should be taken?
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On refrigeration units that use an open compressor; the ________ is most likely to leak if the unit is not used for several months.
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Noncondensables in a system cause?
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Heat pumps that use R-410A should be leak checked with?
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A reciprocating compressor should not be energized when?
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In a refrigeration system, the component directly following the evaporator is the?
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Manifold gauge set hoses should have self-sealing connectors or hand valves to?
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The EPA regulations require that leaking commercial or industrial process refrigeration equipment must be repaired when the leak rate exceeds _____ of the charge per year.
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Moisture is removed from a system by?
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Oil foaming usually occurs in the?
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R-410A is different from other ASHRAE 400 series non-azeotropic blends because?
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With an air-cooled condenser on the roof of a building and the evaporator on the first floor, recovery should first occur?
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A deep vacuum is usually measured in?
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Heat pumps that use R-134A should be leak checked with?
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During the evacuation of a system that contains large amounts of moisture it may be necessary to increase pressure in the system with ________, to counteract the freezing of the moisture.
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Study Notes
System Assembly and Pressurization
- Pressurize new systems with inert gas and perform leak checks.
- After installing R-410A split heat pumps, pressurize with nitrogen before leak checking.
EPA Regulations on Leak Rates
- Appliances with more than 50 pounds of refrigerant must be repaired if the leak rate exceeds 15% per year (excluding commercial and industrial refrigeration).
- Commercial or industrial refrigeration equipment must be repaired when leak rates exceed 35% per year.
R-410A Recovery Requirements
- Recovery tanks for R-410A should be rated for at least 400 psig.
- Recovering liquid refrigerant requires connection to the liquid line.
Recovery Procedures
- Remaining vapor after liquid recovery is condensed by the recovery system.
- Recover R-22 from units previously containing R-502 by evacuating the recovery unit and changing filters.
System Components
- In systems with a TXV, the receiver follows the condenser.
- The accumulator follows the evaporator in a refrigeration system.
Charging and Leak Checking
- Charge R-410A systems with vapor to 120 psig before switching to liquid charging.
- Leak checks for heat pumps using R-410A and R-134A should be done with pressurized nitrogen.
Dealing with Contaminants
- Recovered refrigerant may contain acids, moisture, and oils.
- Moisture is removed from systems using a filter drier.
Compressor and System Maintenance
- On open compressor units, the rotating shaft seal is likely to leak if unused for months.
- Manifold gauge set hoses should have self-sealing connectors or hand valves to minimize refrigerant release during connections.
Noncondensables and Operational Limits
- Noncondensables increase discharge pressure in systems.
- Reciprocating compressors should not be energized with the discharge service valve closed.
Vacuum and Pressure Management
- Deep vacuum measurements are measured in microns.
- During evacuation of moisture-heavy systems, nitrogen may be needed to prevent moisture freezing.
R-410A Properties
- R-410A behaves similarly to azeotropic refrigerants and can be topped off unlike other non-azeotropic blends.
Specific Recovery Situations
- When recovering refrigerant from an air-cooled system with components at different heights, start recovery from the liquid line entering the evaporator.
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Description
Prepare for the EPA 608 Type II Exam with these flashcards. This quiz covers essential concepts such as system pressurization, leak checks, and regulations regarding refrigerants. Test your knowledge and improve your understanding of HVAC best practices.
