After isolating the vacuum pump, a technician watches the micron reading climb steadily and keep climbing without ever leveling off. What does that behavior point to?
Correct Answer
B) A leak drawing outside air into the system, which has to be found before any refrigerant goes in
The decay test separates two problems by watching how the reading behaves. If moisture is still boiling off, the reading rises and then levels out at the saturation pressure of water for that temperature, because the water can only push the pressure so high. If there is a leak, atmosphere keeps feeding in and the reading climbs without limit until it reaches ambient. A reading that rises steadily and never plateaus is the leak signature, and charging a system in that condition just pushes air and moisture in ahead of the refrigerant.
Why This Is the Correct Answer
Air has an unlimited supply outside the system, so a leak drives the pressure up indefinitely. Moisture has a limited supply and a ceiling set by its own saturation pressure, so a wet system rises and stops. The shape of the curve is what identifies the fault, and a leak must be repaired before charging.
Why the Other Options Are Wrong
Option A: Moisture still boiling out of the system, which will settle out once the charge is in
Moisture produces a rise that levels off, not one that keeps climbing. And moisture never settles out on its own once the charge is in; it forms acid and plugs metering devices.
Option C: A normal result caused by the gauge sensor warming up once the pump stops
Micron gauge sensors are not warmed by the pump running, and no normal gauge behavior mimics a continuous pressure rise.
Option D: Refrigerant oil outgassing, which stops on its own once the system is charged
Outgassing tapers off rather than climbing steadily, and it does not stop being a problem simply because refrigerant was added.
Memory Technique
Water hits a ceiling, air does not. Levels off means wet, keeps climbing means leaking.
Reference Hint
40 CFR 82.156 requires the appliance to be evacuated to the applicable level; a system that will not hold vacuum has not met it and cannot be charged.
More epa-608-type-2 Questions
A technician passed Core and Type II but has not taken Type I or Type III. Which unit on the day's work list may that technician open and service without another certified tech present?
A technician reaches the target vacuum, isolates the pump, and confirms that the reading holds steady for several minutes. What is the correct next step?
After brushing soap solution over a unit that loses a small amount of charge every year, a technician sees bubbles forming right at one of the service ports. What is the appropriate repair?
An electronic leak detector alarms continuously as soon as it is switched on inside a closed mechanical room. What should the technician do before trusting any reading from it?
A technician runs a small flow of dry nitrogen through the tubing while brazing new line set into a refrigeration system. What does that flow accomplish?
Before putting a torch to a leaking line, a technician confirms the refrigerant has been recovered and that the tubing has an open path to atmosphere. Why does that open path matter so much?
A supermarket parallel rack holds several hundred pounds of R-404A and runs well above atmospheric pressure on both the suction and discharge sides. Which certification must a technician hold before breaking into that system?
Certification classes split appliances by how the refrigerant inside them behaves. What property puts an appliance in the high-pressure class that Type II certification covers?
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