A technician is about to set the regulator for a dry nitrogen leak test on a split system that includes an accumulator and a receiver. What determines how high that test pressure may be set?
Correct Answer
C) The lowest pressure rating among the components in the section being tested, including the low side and any vessels on it
Everything in the pressurized section sees the test pressure, including the parts with the lowest ratings. Low side components, accumulators, receivers, and any factory-installed relief device generally sit well below what the discharge line can take. The test pressure has to respect the weakest of them, which usually means consulting the equipment nameplate or the manufacturer's service data. Cylinder pressure is irrelevant because that is exactly what the regulator exists to control, and gauge face markings describe the instrument rather than the system.
Why This Is the Correct Answer
When a whole section is pressurized, every component in it is exposed to the same pressure. The limit therefore has to be the lowest-rated part in that section, not the strongest one, and relief devices in the section will lift before anything else if the limit is exceeded.
Why the Other Options Are Wrong
Option A: The pressure the nitrogen cylinder is sitting at on that particular day, since the regulator steadies the flow rather than the pressure
Cylinder pressure is enormous and unrelated to what the equipment can take, and a regulator does exactly what this answer denies. Setting the delivered pressure is the whole reason it sits on the cylinder.
Option B: The normal operating discharge pressure that the system would reach on a hot afternoon under full load
Discharge pressure describes the high side of a running machine. Applying that figure to a static test puts it on the accumulator, the suction piping and the rest of the low side, which are rated well below it.
Option D: The maximum pressure printed on the face of the manifold gauge set that is hooked to the system
The printed maximum on a gauge face describes the range of the instrument and nothing more. A gauge that reads to five hundred psi says nothing about the strength of the vessels it is connected to.
Memory Technique
A chain breaks at the weakest link, and a system leaks at the weakest rating. Set the regulator for that part.
Reference Hint
Test pressure for nitrogen leak testing is limited by the lowest component rating in the pressurized section; follow the equipment manufacturer's specified test pressure.
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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