Topics: All categories in the pool
1: Joints in refrigeration piping must be _____ before being covered?
- Leak tested
- Pressurized
- Inspected
- Insulated
2: What is the temperature that a liquid and a vapor can exist in equilibrium called?
- Saturated temperature
- Wet bulb temperature
- Critical temperature
- Dry bulb temperature
3: Pressure vessels with an internal volume of 3 cubic feet or less
- shall use pressure relief devices
- shall use fusible plugs
- shall use pressure relief devices or fusible plugs
- do not need pressure relief protection
4: A hissing noise at the expansion valve is a good indication that
- expansion valve is oversized
- liquid is passing thru it
- nothing is passing thru
- gas is passing thru it
5: "R" represents ___ in the Ohm's law formula
- voltage
- capacitance
- resistance
- amperage
6: The rupture disc on a low-pressure chiller typically releases pressure at
- 10 psig
- 0 psig
- 15 psig
- 5 psig
7: The total amount of refrigerant stored in a machinery room in all containers not provided with relief valves shall not exceed
- 660 lbs
- 330 lbs
- 500 lbs
- 55 lbs
8: The actual expansion curve of compressor follows most nearly which one of the following
- Pressure-Temperature
- Adiabatic
- Volume
- Isothermal
9: 1 Watt = ______ BTU's?
- 4.482
- 3.412
- 7.216
- 12
10: Which of the following is a drop-in for R-22
- R-410A
- R-134A
- R407C
- None of the above
11: With a 5/8" X 5/8" x 3/4" tee, what size is the center connection?
- 1/2"
- 5/8"
- 3/8"
- 3/4"
12: Total heat of a substance is considered
- empathetical
- sensible heat
- specific heat
- enthalpy
13: The first step in mechanical refrigeration is
- expansion
- evaporation
- compression
- condensation
14: A micron is
- a larger unit of measurement than Hg
- one millonths of a micrometer
- one thousandths of a millimeter
- one millonths of a centimeter
15: When is the only time you can leave a service container attached to a system?
- Leaking system
- Recovery
- Charging
- Both b and c
16: Low ambient controls are used when
- on air conditioning systems only
- always
- economizers are used
- when systems run all year round
17: What type of refrigerants are NOT flammable?
- CHC
- HFC
- HCFC
- All of the above
18: In an A/C unit, dirty filters will cause
- high discharge pressure
- high suction pressur
- low oil pressure
- low suction pressure
19: In a low temperature refrigeration system, the benefit of the system using P.A.G. oil is
- it is hydroscopic
- it traps moisture
- viscosity
- all of the above
20: What type of pressure relief device is used on a CO2 system?
- Glove valve
- Fusible plug
- Rupture disk
- Gate valve
21: Liquid refrigerant flashing, or turning to vapor, in the liquid line may be due to
- liquid line that is too small
- shortage of refrigerant
- liquid line that had too high vertical lift
- All of the above
22: What percentage of amperage difference is allowable phase to phase on a HVAC circuit phased to phase?
- 4%
- 1%
- 25%
- 2%
23: A low oil switch is typically
- non used on semi-hermetic compressors over 10 ton capacity
- automatic reset
- time-delay auto reset
- manual reset
24: Which refrigerant is lighter than air?
- R-11
- R-134a
- R-717
- R-123
25: A EPR valve is installed on what type of evaporators?
- low-temperature evaporators
- shell and tube evaporators
- high-temperature evaporators
- plate evaporators