Chapter 14 (REFRIGERATION) Flashcards
Which of the following could be used to check a leak in ammonia system?
Litmus Paper
Sulfur Stick
Ammonia leaks in the condenser can be detected by
Applying litmus paper to the circulating water discharge
A sulfur stick burning in the presence of ammonia will give off a
dense white smoke
An ammonia leak will turn litmus paper
blue
In an ammonia system the oil gauge must be kept:
closed except when checking oil level
Valves and piping 8n ammonia system are made of:
iron
The relief valve in an ammonia machine is located:
in the compressor head
When purging an ammonia condenser into a bucket of water, one can tell when the air is out and ammonia starts to come through by the:
change of bubbling sound of air to the crackling sound of ammonia
The crossover connection in an ammonia system can be used to
hot gas defrost
How is an ammonia system purged so that operator will not be overcome by the fumes?
into a bucket of water
Thermal expansion valves are usually of the:
diaphragm
bellows type
When checking zinc plates in a condenser, one should:
clean the plates snd renew worn out ones
The scale trap is located between the:
king (liquid) valve snd expansion valve
When the evaporator coils are located in the icebox, the system is known as
direct system
The purge valve is located:
in the highest part of the system
The solenoid valve is:
a temperature controlled stop valve
The thermal expansion valve is located between the:
solenoid valve and the evaporator coils
The purpose of scale trap is to:
remove dirt, scale and metal chips from the refrigerant
The oil separator (trap) is located between the:
compressor discharge valve and the condenser
The charging connection in a refrigerating system is located:
between the king valve and the solenoid valve
The dehydrator is located between the
receiver and the expansion valve
The charging valve is located between the
king valve and the expansion valve
The solenoid valve is located between the
scale trap and the thermal expansion valve
A device used to keep moisture from passing through the system is called
dehydrator
The relief valve is located on the
discharge side of the compressor
The dehydrator is used:
to remove moisture from the system
when adding refrigerant to the system
Which of the following is another name for liquid valve?
king valve
If no gaskets are used in the piping joints of a Freon system, the joints must be:
ground joints
A device for holding open the suction valve snd drawing gas from the suction manifold snd returning it to the suction line without compressing it is called
cylinder unloader
The solenoid valve can be typed as
magnetic stop valve
The bulb for thermal expansion valve is located
near the evaporator coil outlet
The elements of a thermostat switch are usually of the
bimetal type
The expansion valve is located between the
receiver snd evaporator
The oil separator is located between the
compressor and condenser
Zinc rods are found in the
salt water side of condenser
A double trunk piston is used to
all of the above
Which of the following gasket materials should be used on a Freon system?
Asbestos
Metallic
Many pressure gauges on a Freon System have two dials or graduations on one gauge. The two dials represent
pressure and temperature
A double type condenser has
a small pipe inside s larger pipe, the cooling water passing through the small pipe and the refrigerant through the large pipe
When there is a freon leak, the halide torch will burn
green
Large leaks in a Freon system cannot always be detected with a halide torch because ir changer color with the slightest amount of freon present. A large leak can be detected easier by applying
a soapsuds solution, mixed with a little glycerin at to hold the solution together, and watch for bubbles
The relief valve on a CO2 machine is located
on the discharge pipe between the compressor and the discharge valve
The discharge pressure of the compressor should be
the pressure which corresponds to a temperature from 5°F to 15°F higher than the condenser discharge
The purpose if relief valves on regrigeration machines is to:
prevent excessive pressure in case of stoppage on the discharge side of the system
A leaky suction valve can usually be detected by
any of the above
Too low suction pressure could be caused by
any of the above
What do you call a system in which the evaporator coils are located in a brine solution and the brine is pumped through the icebox?
an indirect system
Before securing a compressor to do maintenance work in it, be sure to
purge the system
pump down the system
Obstruction of the expansion valve us usually caused by
any of the above
Excess frost on the evaporator coils
reduces efficiency of the plant
Air circulation in the icebox is accomplished by the use of which of the following?
diffuser fans
The cooling water side of the condenser should be opened for inspection every
three months
