The low stage of a cascade system is charged with R-13, a very high-pressure refrigerant, and the charge is under fifty pounds. What evacuation level does the table set for a very high-pressure appliance?
Correct Answer
B) Zero inches of mercury vacuum with equipment of any age
Very high-pressure appliances have a line of their own in the evacuation table, and both columns of that line read zero inches of mercury vacuum. The age of the recovery equipment makes no difference. The reason is practical: these refrigerants sit at very high pressure at room temperature and cannot be condensed into a recovery cylinder the way ordinary high-pressure refrigerants can, so the rule asks only that the appliance be brought down to atmospheric pressure.
Why This Is the Correct Answer
The very high-pressure row of the evacuation table reads zero inches of mercury vacuum in both the pre-November 1993 and the later column. R-13 and refrigerants like it boil far below the range of the ordinary high-pressure family, and no recovery machine can be expected to pull them into a vacuum, so the required level is simply atmospheric pressure at the appliance.
Why the Other Options Are Wrong
Option A: Four inches of mercury vacuum with newer equipment only
Four inches is a high-pressure figure from the older equipment column. The very high-pressure row carries no equipment-age split at all.
Option C: Ten inches of mercury vacuum with equipment of any age
Ten inches belongs to large R-22 appliances and to smaller charges of the other high-pressure refrigerants, not to the very high-pressure family.
Option D: Twenty-five millimeters of mercury absolute pressure
Twenty-five millimeters of mercury absolute is the low-pressure chiller requirement, at the opposite end of the table from a cascade low stage.
Memory Technique
The coldest refrigerants get the shallowest target. You cannot pull a vacuum on something that boils that low.
Reference Hint
Very high-pressure appliance: zero inches of mercury vacuum, the same in both equipment-age columns.
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?
People Also Study
Business & Financial Management
120 questions · 70% to pass
Contract Administration
60 questions · 70% to pass
Project Management
60 questions · 70% to pass
Related Study Resources
Previous Question
A technician pressurizes a system with dry nitrogen in the afternoon and comes back the next morning to find that the pressure has dropped noticeably. What has to be checked before calling that a leak?
Next Question
A technician opens the electrical panel of a rooftop unit after pulling and locking out the disconnect at the curb. What inside that panel still has to be treated as live?