Topics: All categories in the pool
1: 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
2: RPM's of a centrifugal compressor are at approximately?
- 15,000
- 30,000
- 10,000
- 500
3: What refrigerant doesn't have to be classified?
- R-717
- R-422A
- R-134A
- R-718
4: A secondary coolant is defined as
- a combination of interconnected parts from a closed circuit in where fluid is circulated for the purpose of cooling for a refrigeration system.
- a low temperature refrigerant used for cascading systems
- any refrigerant direcly in contact with the cooling space for process cooling
- any liquid used for the transmission of heat without a change of state in A/C refrigeration systems having flash point above 150F
5: pressure relief valves must discharge to the atmosphere at a location not less than 15 feet from ground level and ____ feet from any window, ventilation opening, or exits of buildings.
- 10
- 15
- 25
- 20
6: Low ambient controls are used when
- when systems run all year round
- always
- on air conditioning systems only
- economizers are used
7: Before you change the type of refrigerant in a refrigeration system, what three things must be done?
- nothing must be done
- place sign, check for leaks, insulate
- make sure it's compatible, notify owner, notify A.H.J
- you can't change refrigerants
8: Fusible plugs shall not be used with pressure vessels of
- 15 square feet or less
- 15 cubic feet or more
- 3 cubic feet or more
- 3 cubic feet or less
9: A room having machinery but no flame producing apparatus permanently installed and operated is considered a
- Class M machinery room
- Class T machinery room
- Class B machinery room
- Class A machinery room
10: While the system is operating, the discharge line should be
- too hot to hold by hand
- room temperature
- at the same temperature as the crankcase
- 10-15F warmer than ambient
11: The proper location for an oil separator is between the
- compressor and condenser
- receiver and metering device
- condenser and receiver
- evaporator and compressor
12: If the compression ratio on a centrifugal compressor rises too high, the compressor will stop pumping and make a loud sound commonly referred to as a
- splurge
- merge
- purge
- surge
13: Pressure vessels shall be provided with ___________in accordance with Section VIII of the ASME Boiler & Pressure Vessel Code
- over pressure protection and a rupture disc
- over pressure protection as well as a temperature protection device
- Pressure vessels need no type of protection as long as it is hydrostatically tested every three months
- over pressure protection
14: How many square inches per square foot?
- 24
- 144
- 64
- 98
15: Pi equals approximately
- 3.41
- 3.14
- 12,000
- 746
16: Which creates more of a heat load?
- 90% RH
- 70% RH
- 50% RH
- 30% RH
17: What is not a requirement of a Class T machine room?
- Self-closing doors
- Fire hose connected to the building fire protection system.
- Tight fitting doors
- Automatic ventilation
18: Two systems using separate refrigerants that are superimposed upon one another is called
- single stage
- indirect
- booster
- cascade
19: Refrigerant restricted in 2004 but used for transition for decades:
- R-11
- R-22
- R-134A
- R-123
20: An azeotropic refrigerant is
- a mixture of two or more refrigerants that boil at about the same temperature minimizing temperature glide.
- a mixture of two or more refrigerants that boil at much different temperatures causing temperature glide
- a mixture of two or more refrigerants that boil at much different temperatures minimizing temperature glide
- none of the above
21: There can be no airflow from an occupied space through a machine room unless what?
- System is high velocity
- System is ducted and sealed
- Duct is not located in the ceiling
- None of the above.
22: An accumulator can be located between the
- evaporator and compressor
- compressor and condenser
- first stage and second stage compressors
- condenser and evaporator
23: Start to Run windings will have what resistance?
- All will be at equal values
- The most resistance value
- Somewhere between the actual start winding and run winding resistance value
- The least resistance value
24: A motor starter contains a thermal overload and a
- transformer
- solenoid
- 3-way relay
- contactor
25: 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