A chiller's purge unit is discharging normally on every cycle, yet the condenser pressure keeps climbing through the afternoon. What does that combination point to?
Correct Answer
A) Air is coming in faster than the purge can remove it, so the leak needs to be found now
A purge that is cycling and actually discharging is working. If non-condensable gas is still accumulating fast enough to drive the head up, the machine is taking air in faster than the purge can pull it out. That is a large leak, and the response is to find it rather than to rebuild the purge. A failed purge looks different: it runs without discharging, and the pressure climbs with nothing leaving the exhaust.
Why This Is the Correct Answer
Purge capacity is finite, measured in ounces of gas per cycle. When the in-leakage rate exceeds it, the condenser accumulates non-condensable gas even though the purge is functioning correctly, and head pressure rises. The distinguishing evidence is that the purge is discharging: the device is doing its job and the machine is simply drinking faster than it can drink.
Why the Other Options Are Wrong
Option B: The purge compressor has failed, so nothing is being removed from the top of the condenser
A failed purge would not be discharging. The fact that gas is leaving the exhaust on every cycle is what rules the purge itself out.
Option C: The condenser water flow has been lost, so the machine is condensing at a higher temperature
Lost condenser water flow raises head pressure too, but it would show as a rise in leaving water temperature and would not drive continuous purge cycling.
Option D: The refrigerant charge is high, so the extra liquid is backing up and flooding the condenser
Overcharge can raise head pressure on some machines, but it does not generate non-condensable gas or keep a purge cycling and discharging.
Memory Technique
Listen at the exhaust. Something coming out blames the machine; nothing coming out blames the purge.
Reference Hint
A functioning purge that cannot hold condenser pressure down indicates an air leak larger than the purge unit's capacity.
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?
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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?
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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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