The maximum test pressure for leak testing a low-pressure centrifugal chiller is - Answer- 10 psig
Excessive operation of a purge system means - Answer- The system has a leak on the sub-ambient pressure side of the sy
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The maximum test pressure for leak testing a low-pressure centrifugal chiller is - Answer- 10 psig
Excessive operation of a purge system means - Answer- The system has a leak on the sub-ambient pressure side of the system
For a commercial refrigeration system with a charge of 50 pounds or more refrigerant, a substantial (or threshold) week rate will be reduced to ________ after January 1, 2019. - Answer- 20%
For a comfort cooling system with a charge of 50 pounds or more of refrigerant, a substantial (or threshold) Leak rate will be reduced to _________ after January 1, 2019. - Answer- 10%
According to the EPA, when all the R-123 liquid has been removed from an average 350 ton R-123 chiller and the system vapor pressure is 0 psig, the system contains - Answer- 100 pounds of refrigerant in the system
When working with low pressure systems, the high-pressure cut off should be set to no more than _________ to avoid damaging the system or activating the pressure blow off device (rupture disk). - Answer- 10 psig
The rupture discs on the low pressure chiller and on the recovery tank should relieve at __________ to prevent damage to the system during refrigerant transfer into or out of the system. - Answer- 15 psig
If possible, the temperature of the equipment room where the chiller is located - Answer- Should be increased to speed recovery
When possible, oil in the chiller should be heated because - Answer- Less refrigerant will be soluble and/or trapped in the oil at higher temperatures
To prevent freezing, when recharging an evacuated water cooled chiller system with R-123, first charge with a vapor 20 pressure of at least - Answer- 20 in Hg vacuum
When recharging a chiller, refrigerant is first added as a vapor followed by a liquid refrigerant to avoid - Answer- Freezing of the water in the chiller barrels
Replacing _________ is always considered a "major maintenance, service, or repair"? - Answer- 1.)An evaporator 2.) condenser 3.)compressor
Low pressure systems must be evacuated to _________ before being discarded. - Answer- 25 mm of Hg absolute
Every recovery and recycling unit must be - Answer- Labeled as certified to meet EPA's requirements
When disposing a system with a normal charge of more than 5 pounds and less than 50 pounds, the disposal record must be kept by the technician for - Answer- 3 years
After reaching the required recovery vacuum, - Answer- Wait a few minutes to see if the system pressure rises before opening the system up for repairs
When does the EPA allow you to not evacuate to the prescribed level? - Answer- When leaks in the appliance make evacuation to the prescribe level unattainable
Replacement of __________ is always considered "major" under EPA's regulations. - Answer- 1.) A condenser 2.) A compressor 3.) An evaporator
At 23.8 in Hg, r-123 boils at approximately: - Answer- 15°F
What can you do to prevent air from entering an evacuated system? - Answer- Introduce nitrogen into the evacuated system to maintain the system pressure slightly above atmospheric pressure
The saturation pressure corresponding to 32°F for R-123 is - Answer- 20 inches of Hg vacuum
According to the EPA, you should take an oil sample if - Answer- The compressor has burned out
Which of the following statements about R-1233zd is true? - Answer- It is a SNAP approved replacement for low pressure centrifugal compressor systems and it can be used in new equipment where R-123 might have been used.
ASHRAE standard 15 requires the use of rooms sensors and alarms to detect - Answer- All refrigerant safety groups
Which safety precautions should be adhered to for low pressure systems? - Answer- Use gloves and safety goggles when working with liquid refrigerant.
When pressurizing a low pressure system for a leak-detection purposes do not exceed - Answer- 10 psig
Where is the purge unit located in a low pressure system? - Answer- The top of the condenser
When leak testing a low-pressure chiller the maximum pressure to use is - Answer- 10 psig
What type of equipment can be worked on with type III certification? - Answer- Low pressure
In a low pressure chiller, air and other non-condensibles collect at the - Answer- Top section of the condenser
If a strong odor is detected during the recovery process - Answer- A compressor burnout may have occurred
Which organization establishes the refrigerant safety group standard? - Answer- ASHRAE
The EPA required evacuation level for recovery or recycling equipment used on low pressure systems is - Answer- 25 mm of Hg absolute
When installing more than one, pressure relief valves must be installed - Answer- In parallel with each other
During evacuation of systems with large amounts of water, it may be necessary to - Answer- Increase pressure by introducing nitrogen to counteract freezing
How long would an equipment owner or operator have to retrofit or retire an appliance that has exceeded the threshold Leak rate if the replacement appliance uses 50 pounds or more of an exempt refrigerant? - Answer- 18 months
Under ASHRAE Standard 34, R-134a is classified as - Answer- A1
To repair a chiller operating with R-22, the technician - Answer- Must have a type 2 certification
When charging a low pressure system, refrigerant should be introduced
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