436 Flashcards
In a cooling system one of the main lines in the piping system is the ___ line
liquid
steel pipe is typically joined by the means of
flanges
tubing is often preferred over piping in a cooling system because it
absorbs vibration better
refrigeration tubing is typically joined by
soldering
when brazing tubing to a fitting you should first heat the ___ until the ___ melts
Tubing; flux
the function of the discharge line in a refrigeration system is to
convey the refrigerant to the condenser
the entrainment of compressor oil is the ___ the moving refrigerant
drawing in and transporting of oil with
in order to keep entrained oil droplets moving through the piping the refrigerant must move at ____ fpm in horizontal piping and ____ fpm in a vertical ariser
500 to 700; 750 to 1,500
refrigerant can be prevented from collecting tin the compressor during the off cycle by installing a ___ in the ___
check valve ; discharge line
accessories often added to a discharge line include a
discharge muffler
subcooling is desirable in the liquid line because it
reduces the volatility of the refrigerant
if the pressure in the liquid line drops flash gas can form which can reduce the
refrigerating effect
with halocarbon refrigerants the movement of oil is better in the liquid line than in the discharge line because the
oil is miscible in mist liquid refrigerants
a liquid receiver is used to
store all the refrigerant during repairs
the purpose of a solenoid valve in the liquid line is to stop the flow of refrigerant to the
evaporator
a double suction riser installed in a cooling system enables the system to operate at maximum load without creating excessive ___ in the suction line
pressure drop
an accumulator in the suction line traps oil and liquid refrigerant to keep it from entering the ___ a heater in the accumulator evaporates the ___
compressor; refrigerant
an evaporator pressure regulator valve closes part way if the pressure at the evaporator outlet becomes too ___ a crankcase pressure regulator valve closes part way if pressure at the compressor inlet becomes too ___
low; high
the suction line is insulated in order to prevent or reduce ___ the line
condensation on the outside of
the amount of oil that can build up in the suction line of an idle single compressor system is much ___ than the amount that can build up in an idle compressor of a multiple compressor system. to prevent damage from excessive oil buildup the suction line should include a trap with the minimum rise of ____ inches
less; 14
piping problems that result in operating problems are often caused by
liquid hammer
which of the following expansion joints can be used in a refrigerant line
bellows
which kind of support is appropriate for a horizontal piping run of 15 feet long
rod type hanger
the problems caused by vibration in the piping of a cooling system include
damage to the valves and controls
insulation is needed on the liquid line if the line is____ than its surroundings. the purpose of insulation on the liquid line is to prevent the loss of any ___ of the refrigerant
much colder; subcooling
