A slow R-410A leak has been narrowed down to a cluster of flare fittings at the outdoor unit, and the technician now needs to identify which single fitting is losing charge. Which method points to the leaking joint most directly at that spot?
Correct Answer
B) Bubble solution brushed onto each fitting so escaping refrigerant forms visible bubbles
Once the leak is narrowed to accessible fittings, bubble solution is the fastest and cheapest way to confirm exactly which joint is losing refrigerant, and the customer can see it too. A halide torch depends on chlorine in the refrigerant, so it does nothing useful on an HFC blend like R-410A and it puts an open flame next to a pressurized system. Ultrasonic detection struggles with the noise of a running condenser fan. Fluorescent dye works well, but it has to circulate through the system before the stain shows, so it is not an on-the-spot answer.
Why This Is the Correct Answer
Bubble solution is a direct visual confirmation at an accessible joint under positive pressure. It costs almost nothing, needs no calibration, works on any refrigerant, and the bubbles form right at the fitting that is leaking rather than somewhere nearby.
Why the Other Options Are Wrong
Option A: A halide torch passed near the fittings so the flame changes color over the leak
A halide torch reacts to chlorine, so it detects CFCs and HCFCs but not chlorine-free refrigerants like R-410A. It also introduces an open flame near a pressurized system and near refrigerant that breaks down into toxic products in a flame.
Option C: An ultrasonic detector swept across the fittings while the condenser fan is running
Ultrasonic detectors listen for the high-frequency sound of gas escaping, which makes them poor at pinpointing small leaks next to a running condenser fan. They are better suited to quiet conditions and larger leaks.
Option D: Fluorescent dye added to the charge and read immediately with a UV lamp
Dye is an effective method but not an immediate one. The dye must circulate with the oil and reach the leak before a stain appears, so it cannot confirm a specific fitting during the same visit.
Memory Technique
Sweep with electronics, confirm with bubbles, and save dye for the leak you cannot catch today.
Reference Hint
Leak detection methods under 40 CFR 82.157: electronic detector, bubble solution, ultrasonic, fluorescent dye, each suited to different conditions.
More epa-608-type-2 Questions
A walk-in cooler condensing unit holds a full charge of twenty-five pounds of R-404A, which is below the fifty pound threshold that brings an appliance under the leak repair provisions. What still applies to this unit?
An office building has thirty water source heat pumps on a common water loop, and each one left the factory assembled, hermetically sealed and charged with four pounds of R-410A. How is one of those units classified?
A data sheet for an unfamiliar refrigerant lists a boiling point of about fifty-five degrees Fahrenheit at atmospheric pressure. What does that tell a technician holding Core and Type II certification?
A technician holds Core, Type I and Type III certification and is sent to recover the charge from a twenty ton rooftop unit charged with R-410A. What does that combination of sections allow on this job?
A fleet garage technician holds only the vehicle air conditioning certification issued under Section 609 and is asked to recover the charge from the shop's own rooftop air conditioner. What does that credential allow?
A split system's outdoor unit, indoor coil and the line set the installer ran and brazed between them are being considered. For the purposes of the refrigerant rules, what makes up the appliance here?
On a new installation the line set is brazed to a factory charged outdoor unit and an indoor coil shipped under a nitrogen holding charge, with the outdoor unit's service valves still closed. What does the recovery requirement call for before that brazing?
A rooftop unit's data plate has weathered until the charge figure cannot be read, and the technician needs the full charge to place the appliance under the evacuation and leak provisions. Where should that figure come from?
A computer room air conditioning unit holds forty pounds of R-407C and connects to a remote air cooled condenser through refrigerant piping run and brazed by the installer. How is that unit classified?
A shop's office manager, who holds no technician certification, is sent to a supply house to pick up a new recovery machine for the commercial crew. What does the sales restriction require at that counter?
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