Refrigeration System Leak Testing

Questions and Answers

What does a hydrostatic tube test kit do?

Determine if a tube leaks.

What is the maximum test pressure when leak testing a low-pressure centrifugal with nitrogen?

10 psig

How may charged low-pressure refrigeration machines be most efficiently leak checked?

Adding heat with circulated hot water or heating blankets.

What should be done to reduce refrigerant loss from a purge unit on an R-123 chiller?

Pipe purge unit back into the low side. Signup and view all the answers

What is the leak rate that requires chillers containing more than 50 pounds of ozone-depleting refrigerant to be repaired?

10% of the charge per year Signup and view all the answers

What is the best method to determine a chiller's normal charge for leak rate calculations?

Use the charge stated on the equipment nameplate. Signup and view all the answers

Who is responsible for keeping records of all leak inspections and repairs?

The owner and/or operator of the equipment. Signup and view all the answers

What is a typical setting for the high-pressure cut-out control on a recovery unit used for evacuating refrigerant from a low-pressure chiller?

10 psig Signup and view all the answers

What starts the refrigerant removal process from a low-pressure system?

Liquid removal. Signup and view all the answers

What must be done after recovering the liquid refrigerant from a low-pressure chiller?

Recover the vapor refrigerant. Signup and view all the answers

Approximately how much refrigerant vapor is left in an average 350-ton R-123 chiller at 0 psig once all the R-123 liquid has been removed?

100 pounds Signup and view all the answers

What could happen with the use of a severely oversized vacuum pump when evacuating a system?

Cause trapped water to freeze. Signup and view all the answers

After system servicing and recharging, why is refrigerant vapor reintroduced to the chiller before refrigerant liquid?

Liquid charged into a deep vacuum will evaporate and may lower the temperature, freezing water in the heat exchanger tube bundle. Signup and view all the answers

What should you do after reaching the required recovery vacuum on a low-pressure appliance?

Wait for at least a few minutes to see if the system pressure rises before charging. Signup and view all the answers

Which action is always considered 'major' under EPA's regulations?

Replacement of an evaporator coil. Signup and view all the answers

When should an appliance not be evacuated all the way to the prescribed level?

When leaks in the appliance make evacuation to the prescribed level unattainable. Signup and view all the answers

Which statements are true of recycling and recovery equipment?

It must be labeled as certified to meet EPA's requirements. Signup and view all the answers

What method can be used to pressurize an R-1233zd system for the purpose of opening it for a non-major repair?

Warming the liquid refrigerant in the system. Signup and view all the answers

How long must a technician evacuating refrigerant from appliances with a full charge of more than 5 pounds and less than 50 pounds keep records of the event?

3 years Signup and view all the answers

What is the primary purpose of a purge unit on a low-pressure chiller?

Remove non-condensables from the system. Signup and view all the answers

Where does the purge unit on a centrifugal system take its suction?

Top of the condenser. Signup and view all the answers

At what approximate temperature does R-123 boil at 14.7 PSIA?

82°F Signup and view all the answers

Where does refrigerant go after it leaves the purge unit of a low-pressure centrifugal system?

The evaporator. Signup and view all the answers

What does ASHRAE Standard 15-2013 require the use of room sensors and alarms to detect?

Refrigerant leaks. Signup and view all the answers

What does ASHRAE Standard 15-2013 require in relation to refrigerant safety groups?

It requires the use of sensors and alarms to detect all refrigerant safety groups. Signup and view all the answers

Study Notes

Leak Testing and Refrigeration Systems

A hydrostatic tube test kit is used to detect leaks in tubes.
The maximum test pressure for leak testing low-pressure centrifugal systems with nitrogen is 10 psig.
Efficient leak checking for charged low-pressure refrigeration machines involves adding heat through circulated hot water or heating blankets.

Refrigerant Management and Safety Regulations

To minimize refrigerant loss from an R-123 chiller's purge unit, it should be piped back into the low side of the system.
Since 2019, EPA regulations require chillers containing more than 50 pounds of ozone-depleting refrigerant to be repaired if the leak rate exceeds 10% of the charge annually.
The normal charge for leak rate calculations on a chiller should align with the charge specified on its nameplate.

Responsibilities and Reporting

The owner or operator of refrigeration equipment is responsible for maintaining records of leak inspections and the completion of leak repair verification tests.

Refrigerant Recovery and Evacuation Procedures

Typical high-pressure cut-out control settings for recovery units evacuating refrigerant from low-pressure chillers is 10 psig.
Refrigerant removal from low-pressure systems begins with liquid removal, followed by vapor recovery after the liquid is extracted.
In an average 350-ton R-123 chiller at 0 psig, approximately 100 pounds of refrigerant vapor remains after liquid extraction.

Vacuum and Evacuation Techniques

Using an oversized vacuum pump can result in trapped water freezing during the evacuation process.
Vapor refrigerant is introduced to a chiller before liquid to prevent the freezing of water in the heat exchanger due to low temperatures from evaporated liquid.
Upon reaching the required recovery vacuum in a low-pressure appliance, it's advised to wait a few minutes to check for pressure rise before charging.

Major Actions and EPA Compliance

Major actions under EPA regulations include the replacement of an evaporator coil.
Evacuating an appliance to prescribed levels is not recommended if leaks prevent reaching those levels.
Recycling and recovery equipment must be labeled as certified to meet EPA requirements.

Pressurization and Record Keeping

For non-major repairs in an R-1233zd system, the liquid refrigerant can be warmed to pressurize the system for access.
Technicians must keep records of refrigerant evacuation from appliances with full charges of more than 5 pounds but less than 50 pounds for three years.

Purge Units and Refrigerant Properties

The primary function of a purge unit in a low-pressure chiller is to eliminate non-condensables from the system.
The purge unit on a centrifugal system takes suction from the top of the condenser.
R-123 at 14.7 PSIA boils around 82°F.

Refrigerant Pathways and Standards Compliance

After passing through the purge unit, refrigerant in a low-pressure centrifugal system flows to the evaporator.
ASHRAE Standard 15-2013 mandates the use of room sensors and alarms to detect refrigerant leaks and applies to various refrigerant safety groups.

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Description

This quiz covers essential principles of leak testing in refrigeration systems, including hydrostatic testing techniques and safety regulations regarding refrigerant management. Participants will learn about EPA regulations on leak repairs and responsibilities for record-keeping. Test your knowledge on effective leak detection strategies and compliance measures.