Ingersoll-Rand Thermo King V-520 10, Operator'S Manual, Page: 66 / 74

Glossary
66
fusible link: An electrical safety device (typically a short
piece of wire) inserted into an electrical circuit. The wire melts
or breaks when the current is increased beyond a specific
value. When this occurs, the circuit is opened and electrical
current flow is stopped.
HCFC: Hydrochlorofluorocarbon. A chlorine-based
refrigerant containing hydrogen, chlorine, fluorine and carbon.
Example: R22. Because chlorine damages the earth’s
atmosphere, in many countries, it is illegal to release this type
of refrigerant to the atmosphere. HCFC refrigerants are not
used in modern Thermo King units.
Hertz: A unit of frequency equal to one cycle per second.
Abbreviated “Hz.”
HFC: A refrigerant consisting of hydrogen, fluorine and
carbon. Examples: R134a and 404A. HFC refrigerants contain
no chlorine and are, therefore, considered “safe” for the
environment.
high pressure relief valve: A safety valve on the
refrigeration system that allows refrigerant to escape from the
system if pressure exceeds a predetermined value.
hp (horsepower): A unit of power equivalent to 746 watts
or 550 foot-pounds per second.
HPCO (High Pressure Cut Out Switch): A
pressure-operated switch that opens to stop unit operation
when discharge pressure reaches a predetermined maximum.
invertible: A multi-temperature truck or trailer unit designed
to allow the placement of deep-frozen cargo in any
compartment. See
Multi-Temp.
kPa: Kilopascals. A metric unit of pressure. 1 kPa = 0.01 bar =
0.145 psi.
load: 1) The product being refrigerated and transported.
2) The amount of heat being removed by the refrigeration
system. (For example, a compressor is under a heavy heat load
when expected to cool a very warm box.)
LPCO (Low Pressure Cut Out Switch): A
pressure-operated switch that opens to stop unit operation
when suction pressure reaches a predetermined minimum.
modulation: An optional system that reduces load (product)
dehydration and avoids “top freeze.”
Glossary
66
fusible link: An electrical safety device (typically a short
piece of wire) inserted into an electrical circuit. The wire melts
or breaks when the current is increased beyond a specific
value. When this occurs, the circuit is opened and electrical
current flow is stopped.
HCFC: Hydrochlorofluorocarbon. A chlorine-based
refrigerant containing hydrogen, chlorine, fluorine and carbon.
Example: R22. Because chlorine damages the earth’s
atmosphere, in many countries, it is illegal to release this type
of refrigerant to the atmosphere. HCFC refrigerants are not
used in modern Thermo King units.
Hertz: A unit of frequency equal to one cycle per second.
Abbreviated “Hz.”
HFC: A refrigerant consisting of hydrogen, fluorine and
carbon. Examples: R134a and 404A. HFC refrigerants contain
no chlorine and are, therefore, considered “safe” for the
environment.
high pressure relief valve: A safety valve on the
refrigeration system that allows refrigerant to escape from the
system if pressure exceeds a predetermined value.
hp (horsepower): A unit of power equivalent to 746 watts
or 550 foot-pounds per second.
HPCO (High Pressure Cut Out Switch): A
pressure-operated switch that opens to stop unit operation
when discharge pressure reaches a predetermined maximum.
invertible: A multi-temperature truck or trailer unit designed
to allow the placement of deep-frozen cargo in any
compartment. See
Multi-Temp.
kPa: Kilopascals. A metric unit of pressure. 1 kPa = 0.01 bar =
0.145 psi.
load: 1) The product being refrigerated and transported.
2) The amount of heat being removed by the refrigeration
system. (For example, a compressor is under a heavy heat load
when expected to cool a very warm box.)
LPCO (Low Pressure Cut Out Switch): A
pressure-operated switch that opens to stop unit operation
when suction pressure reaches a predetermined minimum.
modulation: An optional system that reduces load (product)
dehydration and avoids “top freeze.”