Beyond logging purge run time, what routine laboratory check tells a chiller owner that air and moisture have been getting into the machine?
Correct Answer
B) A sample of the refrigerant and oil analyzed for moisture content and acid formation
Air brings water into the machine, and water and refrigerant together form acid. Sending a refrigerant sample and an oil sample to a laboratory once a year produces numbers for moisture and acidity that can be tracked from season to season. A rising trend is evidence of air ingress and of damage in progress, and it usually appears before anything shows up in the machine's operating readings. Falling numbers after a repair confirm that the repair worked.
Why This Is the Correct Answer
Laboratory analysis of the refrigerant and the oil measures the two things air ingress actually leaves behind: moisture and acid. Because the results are numbers rather than impressions, they can be trended across years, which turns a vague concern about a leaking machine into evidence an owner can act on and budget for.
Why the Other Options Are Wrong
Option A: A hardness test of the condenser water, showing how much scale is forming inside the tubes
Water side hardness tells you about scale and water treatment. It says nothing about what has entered the refrigerant side.
Option C: A vibration survey of the compressor, showing whether the bearings have begun to wear
Vibration analysis catches mechanical wear, some of which is caused by acid attack, but it reports the consequence rather than the moisture that produced it.
Option D: A power reading at the starter, showing how far the machine has drifted from its design draw
Power draw rises with non-condensable gas as well as with fouling and load, so it cannot distinguish air ingress from several other causes.
Memory Technique
The oil remembers every gallon of air the machine ever drank. Send it to the lab and ask.
Reference Hint
Annual refrigerant and oil analysis for moisture and acid documents air ingress into a low-pressure machine.
More epa-608-type-3 Questions
Some jobs on a chiller count as a major repair under the refrigerant rules, which changes what a technician is allowed to do with a badly leaking machine. Which job falls into that category?
An owner asks how many pounds of refrigerant the rules allow to be left inside a chiller once the recovery has been signed off. What is the correct answer to give him?
The motor of a hermetic centrifugal chiller sits inside the pressure boundary rather than outside it on a shaft. What follows from that construction?
An oxygen monitor is used to decide whether a chiller machine room is safe to enter after a refrigerant release. Below what oxygen reading is the atmosphere treated as oxygen deficient?
A low-pressure chiller's rupture disc has a discharge line running from it. Where does that line have to terminate?
A refrigerant vapor detector in a chiller machine room reaches its alarm level. Besides sounding, what is that alarm expected to do?
Which piece of equipment requires a technician to hold Type III certification before it may be serviced?
What property of the refrigerant is what actually places an appliance into the low-pressure category?
During normal operation, what condition exists inside the evaporator of a running low-pressure centrifugal chiller?
In what unit is the required final recovery vacuum for a low-pressure appliance normally expressed?
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