The collar of a refillable recovery cylinder is stamped with a tare weight. What does that stamped figure tell the technician?
- AThe highest pressure the cylinder may be exposed to while it is being filled, marked in pounds for convenience
Cylinders do carry a service pressure marking, but it is stamped separately and expressed in psi rather than pounds of weight. Reading the tare stamp as a pressure limit mixes up two different markings on the same collar.
- BThe total weight of the cylinder once it holds its full rated charge, which is the figure the scale should read when filling stops
Tare is the empty weight, not the loaded weight. A technician filling until the scale reached the tare figure would stop before any refrigerant went in, and one treating a full cylinder as tare would badly overfill it.
- CThe number of pounds of refrigerant the cylinder is permitted to hold before the fill limit is reached
The permitted quantity comes from the rated capacity and the fill limit, not from the tare stamp. Tare accounts only for the steel and the valve, so using it as a capacity figure ignores the eighty percent rule.
- The weight of the empty cylinder with its valve, which is subtracted from the scale reading to find the refrigerant weight
Why D is correct
Tare weight is the empty weight of the cylinder and valve. Gross weight on the scale minus tare weight equals net refrigerant weight, and net weight is the figure compared against the cylinder rated capacity when deciding whether it is safe to keep filling.
What this question is testing
This item checks whether the candidate can read basic cylinder stampings and understands the arithmetic relationship between gross weight, tare weight, and net refrigerant weight.
On the job
Cylinders vary in empty weight by several pounds depending on size and manufacturer, so a shop cannot assume one number for the whole rack. Techs who work off gross weight alone eventually overfill a heavy cylinder or stop far short on a light one. Reading tare off the collar takes seconds and turns the scale into a real measurement. Reclaimers also use tare to verify how much recovered product actually arrived.
Memory technique
Tare rhymes with bare: the bare cylinder with nothing in it.
Exam tip
Tare equals empty. If an answer describes a full or loaded weight, it is the wrong stamping.
Where to look it up
Tare weight is stamped on the collar and equals the empty cylinder plus valve; gross minus tare equals refrigerant weight.