Topics: All categories in the pool
1: What type of fuses must be used on a HVAC system?
- TR Type, Duel Element, Time Delay
- Fast blow
- 10% lower than RLA
- none of the above
2: What instrument is used to measure very high resistance?
- voltmeter
- tape measure
- ammeter
- meg ohmmeter
3: When a pressure gauge is permanently installed on a system, it must be ___ times the design pressure of the system.
- 2.2
- 1
- 1.2
- 1.5
4: All low-pressure chillers use which type of compressor?
- Reciprocating
- Rotary
- Scroll
- Centrifugal
5: A mercury bulb controller is not recommended for
- use where vibration is severe
- line or low voltage use
- line voltage use
- low voltage use
6: Where must a refrigeration contractor's license number be displayed?
- Trucks, license plates, and uniforms
- Trucks, invoices, and advertising
- Truck, office, every job, and on all equipment
- Uniforms, checks, and invoices.
7: 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.
8: RPM's of a centrifugal compressor are at approximately?
- 30,000
- 10,000
- 15,000
- 500
9: What type of voltage causes the winding in a potential relay to open?
- BEMF (Back Electro-Motive Force)
- 24V control voltage from the thermostat
- 120V line voltage
- None of the above
10: On a large centrifugal system, what meters the flow to the evaporator?
- High side float
- Cap tube.
- TXV
- Low side float
11: When is the space above a drop ceiling calculated as space for refrigerant limit quantities?
- When there is a space 6' or more above it
- When there are sprinklers above
- When its white
- When it's used as part of a supply or return air system
12: Horizontal piping should be run level.
- Yes, if the condenser is located above the evaporator
- True
- False
- No, unless the supervisor on the job says so.
13: What is the voltage of each leg to ground of a three-phase motor with a 460v supply voltage?
- 120v
- 240v
- 277v
- 208v
14: Adjusting the spring pressure on a TXV
- makes no difference
- changes superheat
- changes subcooling
- adjusts the bulb charge
15: The test pressure applied to the high side of each factory-assembled refrigerating system shall be at least equal to the design pressure of
- the aggregate of the high side and low side
- 2.5 times the design pressure
- the high side
- the low side
16: R22 and 410A operate at the same range of condensing and evaporating temperatures
- true
- false
17: According to ASHRAE Standard-15 9.8 Positive Displacement Compressor Protection, the pressure-relief device discharge into
- the low-pressure side of the system
- the high side of the system
- the liquid receiver
- both a and c are correct
18: What effect does the temperature of air have on humidity?
- warmer air holds more moisture then cooler air
- cooler air holds more moisture then warmer air
- air has no effect of humidity
- none of the above
19: A premise where large numbers of people congregate and from which occupants can not quickly vacate the space is considered
- commercial occupancy
- institutional occupancy
- mixed occupancy
- public assembly occupancy
20: What is a megaohm meter?
- An electric meter that measures very high resistance values by sending a low voltage AC signal into the object being tested
- An electric meter that measures very high resistance values by sending a high DC voltage signal into the object being tested
- Is an electric meter that measures extremely low resistance valves by sending high DC voltage signal into the object being tested.
- An electric meter used by electricians to test large 3-phase blower motors for the correct rotation
21: How many refrigerant classifications are there for toxicity?
- 3
- 1
- 2
- 5
22: In an air conditioning plant which an indirect low side, water is used inside of bring: the proper sequence of operating the plan is
- start the comrpessor
- reset the safety valve
- reset the expansion valve
- start the fan and circulating pump
23: Control systems can be classified by
- economy of operation
- source of power
- tonnage of system
- safety
24: The principle used in continuous type absorption systems is
- Boyle's Law
- Charles's Law
- Ohm's Law
- Dalton's Law
25: Systems containing more than 110 pounds must have stop valves located at the
- compressor suction inlet
- compressor discharge outlet
- receiver inlet and outlet
- All of the above