Topics: All categories in the pool
1: The level of voltage caused by back electromagnetic force that opens the contacts of a potential relay in order to take the start capacitor out of the circuit is
- run voltage
- boost voltage
- lift voltage
- pick-up voltage
2: A R-22 system running with a condensing temperature of 110F and a 40F evaporator temperature will read pressures of ____ on the high side and ____ on the low side.
- 226 psig, 68 psig
- 257 psig, 77 psig
- 350 psig, 120 psig
- 455 psig, 185 psig
3: B3 refrigerants are considered
- non-toxic but non-flammable
- toxic and highly flammable
- toxic but non-flammable
- non-toxic but flammable
4: Which refrigerant(s) is an HFC?
- R-22
- R-410A
- R-502
- All of the above
5: In designing duct work, pressure and ______ need to be considered
- length
- CFM
- duct sealant used
- all of the above
6: What is absolute humidity?
- the amount of moisture in the air per one pound of 50% RH air
- the amount of moisture in the air in grains of cubic feet of volume
- the amount of moisture in the air in grains of square feet of volume
- none of the above
7: The difference between saturated liquid and saturated vapor is
- pressure
- temperature
- volume
- heat
8: The Department that certifies the transportation of refrigerant is the
- EPA
- EPO
- DOT
- RSES
9: A 24 volt transformer with a 240 volt primary can handle how many amps?
- 10 amps
- 24 amps
- There isn't enough information to answer.
- 20 amps
10: A compressor that increases vapor pressure by changing the internal volume of the compression chamber is called?
- Pressure induced displacement.
- Non-positive displacement
- Positive displacement
- Low Pressure displacement
11: What refrigerant has zero ozone depletion
- HFC
- CFC
- HCFC
- None of the above
12: What is specific heat?
- measured heat
- heat required to raise the temperature of 1lb of a substance 1 degree
- the specific heat required to change the state of one cubic foot of air to steam
- none of the above
13: Each machinery room shall contain
- smoke and fire alarms as well as three means of egress and that egress must meet 528 CMR ventilation requirements
- high and low pressure controls
- a refrigerant detector located in an area where the refrigerant from a leak will concentrate
- a toxicity detector where the presence of ammonia or lithium bromide from a leak will concentrate
14: Pressure vessels with an internal volume of 3 cubic feet or more
- shall use pressure relief devices
- shall use pressure relief devices or fusible plugs
- do not need pressure relief protection
- shall use fusible plugs
15: The two basic types of evaporators are
- flooded and direct expansion
- prime surface and finned
- finned and plate
- direct expansion and plate
16: What is a high-side float?
- Located in the evaporator, is a float-type metering device that rises to reduce refrigerant flow when the liquid refrigerant level rises in the low side of the chiller
- Located in the liquid line entering the evaporator, is a float-type metering device that rises to reduce refrigerant flow when the liquid refrigerant level rises in the high side of the chiller
- An electronic-type metering device that contains a float assembly within the device which can accurately meter refrigerant into the evaporator as the load varies
- Located in the liquid line entering the evaporator, so when the refrigerant level is higher in the liquid line than the evaporator, the float rises to allow more refrigerant flow into the evaporator
17: A chilled water pump's suction gauge reads 10 psig. The discharge gauge reads 48 psig. What is the head in feet the pump is working against?
- 38
- 96
- 58
- 88
18: How many gallons of water do you need per pound of ammonia?
- 50
- 1
- 100
- 10
19: When liquid receivers are used, the liquid refrigerant shall not exceed _______percent of the volume at 90F.
- 99%
- 90%
- 75%
- 80%
20: When can 50/50 solder be used?
- in the low side
- in the high side
- liquid and suction lines
- none of the above.
21: The ____ design is the maximum pressure for which a specific part of a refrigeration system is designed.
- high pressure
- critical pressure
- low pressure
- design pressure
22: The best way to detect ammonia in brine is
- potassium of line
- carbonation of soda
- CO2 gas
- nessler regaent
23: On a ammonia compressor, the pressure of a forced fed oil pump is changed by varying the
- adjustment of the spring tension of the TXV
- cooling temperature set-point
- opening at the pump outlet
- opening at the pump inlet
24: Joints in refrigeration piping must be _____ before being covered?
- Pressurized
- Insulated
- Leak tested
- Inspected
25: What device removes the start winding from the circuit of a split-phase motor once the motor reaches 75% of its rated load amps (RLA)?
- duel-voltage switch
- motor starter
- printed circuit board (PCB)
- centrifugal switch