A technician has to leave refrigerant and nitrogen cylinders on a roof for several hours during a long change-out. How should those cylinders be handled while they sit there?
Correct Answer
D) Stood upright and secured against tipping, out of direct sun so heat does not drive the pressure up
Cylinders belong upright and restrained, with the valve protection in place when they are not in use. Upright keeps the relief device in the vapor space where it can function as designed, and securing them keeps a tipped cylinder from shearing a valve. Sun and hot surfaces raise the temperature of the liquid inside, which raises the pressure directly, so shade matters on a roof in summer. A cylinder is never left with its valve open, since that is a deliberate release and it empties the cylinder.
Why This Is the Correct Answer
Upright placement keeps the pressure relief device in contact with vapor rather than liquid, securing prevents a fall that can break off a valve, and keeping cylinders out of the sun holds the liquid temperature down so the internal pressure stays within the range the cylinder and its relief device were designed around.
Why the Other Options Are Wrong
Option A: Laid down flat on the roof deck so that wind and foot traffic cannot tip them over
On its side a cylinder's relief device may sit in liquid instead of vapor, which changes how it behaves in an overpressure event. Cylinders are stored and used standing upright and secured.
Option B: Set close against the unit's hot condenser coil so they stay warm and hold enough pressure to charge with
Deliberately warming a cylinder raises the pressure inside it, which is the hazard being guarded against. Heat is what overfilled cylinders fail from, and a running condenser is a heat source.
Option C: Left with the valve cracked slightly open so internal pressure cannot build while they sit
An open valve is a deliberate release, which is prohibited, and it empties the cylinder besides. Pressure is managed by keeping the cylinder cool and correctly filled, not by venting it.
Memory Technique
Stand them up, strap them down, keep them cool, keep them shut.
Reference Hint
Cylinders are stored and used upright and secured; heat raises internal pressure. Venting refrigerant to atmosphere is prohibited.
More epa-608-type-2 Questions
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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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