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25 Cards in this Set
- Front
- Back
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Where should the discharge from a rupture disc be piped for venting? |
Outdoors |
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What is the typical design burst pressure for a rupture disk on a low-pressure centrifugal air-conditioning system? |
15 psig |
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What is a typical advantage of a water cooled recovery unit? |
Faster recovery of large quantities of refrigerant. |
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Why must water be circulated through a chiller during refrigerant evacuation? |
To prevent freezing of water in the appliance. |
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After system servicing, and recharging, why is refrigerant vapor re-introduced 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. |
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How do you determine when enough vapor has entered the refrigeration system before you charge refrigerant liquid? |
Refrigerant saturation temperature increases above 32°F. |
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What evacuation level must technicians recover refrigerant to before disposing a low-pressure appliance? |
25 mm of Hg absolute |
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Which of the following always falls under the EPA definition for “major maintenance, service, or repair ” |
Replacing a compressor |
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What is the primary purpose of a purge unit on a low-pressure chiller? |
Remove non-condensables from the system. |
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Where is the rupture disc located on a centrifugal chiller? |
Evaporator |
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A hydrostatic tube test kit will; |
Determine if a tube leaks. |
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When leak testing a low-pressure centrifugal chiller with nitrogen, what is the maximum test pressure? |
10 psig |
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What should be done to reduce refrigerant loss from a purge unit on a R-123 chiller? |
Leak test and repair the chiller. |
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Leak testing a low-pressure refrigeration system with nitrogen in excess of 10 psig could cause which of the following to fail? |
Rupture disc |
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Which component is particularly susceptible to leaks in low-pressure refrigeration systems with open-drive type compressors? |
Shaft seal |
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Starting in 2019, EPA regulations require that all chillers containing 50 or more pounds of ozone-depleting refrigerant that are used for comfort cooling be repaired when the leak rate exceeds; |
10% of the charge per year. |
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Starting in 2019, EPA regulations require that leaking industrial process refrigeration with ozone-depleting refrigerant be repaired (or retrofitted or retired) when the leak rate exceeds; |
30% of the charge per year. |
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The EPA’s leak repair requirements apply to appliances with a charge size of; |
50 pounds or greater. |
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What must a system owner do, once the threshold leak rate has been exceeded on any low-pressure system using an ozone-depleting refrigerant? |
Repair the appliance enough to bring the leak rate below the threshold, retrofit, or retire the appliance. |
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What is the best method to determine a chiller’s normal charge for leak rate calculations? |
Use the charge stated on the equipment nameplate. |
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Starting in 2019, what is the leak rate threshold for commercial refrigeration equipment with a full charge of 50 or more pounds of an HCFC refngerant? |
20 % |
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Starting in 2019, what is the leak rate threshold for industrial process refrigeration equipment with a full charge of 50 or more pounds of an HCFC refrigerant? |
30% |
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Starting in 2019, what is the leak rate threshold for comfort cooling appliances with a full charge of 50 or more pounds of an HCFC refrigerant? |
10% |
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How long must owners and operators of low-pressure chillers using HCFC refrigerant keep records of leak inspections, initial verification, and follow-up verification tests? |
3 years |
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A typical setting for the high pressure cut-out control on a recovery unit used for evacuating the refrigerant from a low-pressure chiller is; |
10 psig |
