Topics: All categories in the pool
1: What is the state of the refrigerant leaving the evaporator?
- low temperature superheated vapor
- a high temperature superheated vapor
- a high temperature subcooled liquid
- a low temperature subcooled liquid
2: 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
3: Heat transferred by conduction from one body to another is done
- via heat rays
- via radiation
- via liquids
- via solids
4: What happens to copper joints when overheated?
- nothing
- joint becomes oxidized and ditorted
- copper becomes harder
- none of the above
5: R-718 is rated unlimited for refrigeration quantity contained in a system. Why?
- Because it's cheap
- Because it's a non-flammable refrigerant
- R-718 is not rated unlimited because it's a dangerous refrigerant
- Because it's water
6: A tachometer is an instrument used to measure
- RPM
- air velocity
- speed
- static pressure
7: Usually dry bulb temperature is
- same as wet bulb temperature
- higher than wet bulb temperature
- lower than dry bulb temperature
- not important and shall be ignored
8: When testing systems using non-positive displacement compressors, the entire system shall be considered for test purposes as the low side.
- True
- False
9: "E" references ____ in the Ohm's law formula
- resistance
- voltage
- amperage
- capacitance
10: Liquid level gauges must be provided with what?
- A red line
- A low level mark
- Automatic shut-offs
- A relief valve
11: What device measures the specific gravity of a substance?
- Hydrometer
- Thermometer
- Manometer
- Hygrometer
12: On a single phase motor, when does the start winding cut out?
- At 50% of its full rated speed
- At 75% of its full rated speed
- Start windings do no cut-out of the run cycle
- At 25% of its full rated speed
13: Joints in piping for refrigeration containing parts must withstand temperatures of ___?
- 600F
- 700F
- 800F
- 1000F
14: The main purpose of the accumulator is to
- provide space for vapor to accumulate
- prevent liquid slugs at the compressor
- store liquid refrigerant
- provide space for the accumulation of oil and containminants
15: Mercury was used in thermometers primarily because it
- was inexpensive
- expands uniformly
- never freezes
- vaporizes at very high temperatures
16: An example of direct system is
- rooftop unit
- chiller
- absorber
- none of the above
17: A halide torch is most useful with a freon compression system
- to sweat flanges on the refrigeration piping
- to remove from from TXV's and evaporator coils
- to release a sticking valve
- to detect refrigeration leaks in piping joints
18: What should never be used in pressure testing refrigeration systems?
- Oxygen
- Compressed air
- Nitrogen
- Both a and b
19: All low-pressure chillers use which type of compressor?
- Scroll
- Rotary
- Centrifugal
- Reciprocating
20: Which refrigerant(s) is an HFC?
- R-22
- R-410A
- R-502
- All of the above
21: The difference between saturated liquid and saturated vapor is
- heat
- pressure
- temperature
- volume
22: A water regulating valve opens when
- when the power is on there is an overcharge of refrigerant
- when the power is on
- the head pressure rises
- the compressor is on
23: Liquid line filter-driers on a 410A system must be rated for no less than
- 400 psig
- 1000 psig
- 200 psig
- 600 psig
24: Low-side system leaks in a low-pressure chiller will often result in
- system refrigerant leaking from the system
- nitrogen leaking out of the system.
- water being pulled into the system
- air being pulled into the system
25: If the spring is adjusted to increase the superheat, this new setting will
- shorten the frost line
- allow more liquid into the evaporator
- lengthen the frost line
- have no effect on the frost line