Topics: All categories in the pool
1: The purpose of an accumulator is to
- filter out impurities from the system
- store excess refrigerant from the reciver
- assure no liquid returns to the compressor
- reduce friction loss to the flow of refrigerant
2: On a centrifugal compressor, stationary diffuser vanes are needed to
- prevent high pressure on the packing
- stop gas flow
- convert velocity energy to pressure
- increase the clearance space
3: An example of direct system is
- rooftop unit
- chiller
- absorber
- none of the above
4: A split-phase motor has a ______ winding and a ____ winding
- start, common
- run, common
- duel-run, duel-start
- run, start
5: Halogen refrigerants are corrosive to which type of metal?
- copper
- stainless steel
- black iron
- magnesium
6: A secondary coolant is defined as
- a low temperature refrigerant used for cascading systems
- any liquid used for the transmission of heat without a change of state in A/C refrigeration systems having flash point above 150F
- any refrigerant direcly in contact with the cooling space for process cooling
- a combination of interconnected parts from a closed circuit in where fluid is circulated for the purpose of cooling for a refrigeration system.
7: What's the purpose of a megohmmeter?
- To measure low to very low resistance values
- To alternate the current in a DC circuit in order to calculate the total impedance of a circuit
- To measure very high resistances
- None of the above
8: With a 5/8" X 5/8" x 3/4" tee, what size is the center connection?
- 3/8"
- 3/4"
- 1/2"
- 5/8"
9: What should not (and can not) be located between a pressure imposing device and a pressure-limiting device?
- Muffler
- Stop valve
- Foot valve
- Moisture indicator
10: In a refrigeration system, you open a valve from the condenser and collect some material on a clean white sheet of bond paper, which of the following would you most likely be testing for?
- checking the level of refrigerant in the system
- testing for oil in the system
- testing for moisture in the system
- none of the above
11: Sensible heat is the heat added to a substance to
- freeze it
- raise its temperature
- change its state
- cause evaporation
12: The dial of a pressure gauge, when installed on the high side of a system be graduated 1.2 times the designed pressure.
- True
- False
13: No open flames are allowed in the machinery room unless?
- Only when combustion air is provided from outside of the machinery room
- Approved by the installing contractor
- Never can be allowed
- Approved by the authorized person
14: What kind of material can't be used on the outlet of a relief valve?
- Stainless Steel
- Copper
- Aluminum
- PVC
15: How does a centrifugal compressor create the pressure differential needed to move refrigerant through the system?
- Fan-like action
- Suction and discharge valves
- Nesting scrolls
- Rotating vanes
16: Starting relays for a single phase compressors are used to remove the starting circuit from operation when the motor reaches approximately ____ percent of its speed.
- 75
- 100
- 24
- 50
17: How many volts would you read on a 480V system phase to phase?
- 1/3 the voltage
- 480
- 277
18: What type of copper is not permitted on refrigeration systems?
- Type K
- Type N
- Type L
- Type M
19: Large Mercantile occupancy is a premise or that portion of a premise where more than ____ persons congregate on levels above or below the street level to purchase personal merchandise.
- 250
- 350
- 400
- 100
20: Where a refrigeration or air conditioning system is installed,
- A field inspection shall be made before it is put into service
- it shall not be operated below prescribed pressuers
- The company who installed the system must notify the fire department in the jurisdiction where installed
- the form or certificate shall be authorized by the Department of Public Safety
21: Can a R22 line set be reused for a 410A system and if it can be reused, what must be done to it?
- Flush with ammonia
- Flush with R-718
- Flush with R-11
- Flush with RX-11
22: The best way to detect ammonia in brine is
- potassium of line
- carbonation of soda
- CO2 gas
- nessler regaent
23: Capacity control on a centrifugal compressor is accomplished by the
- slide vanes
- check valves
- pre-rotational guide vanes
- post-rotational guide vanes
24: Institutional occupancy is
- a premise or that portion of a premise where large numbers of people congregate and from which occupants cannot quickly vacate the space.
- a premise or that portion of a premise from which, because they are disabled, debilitated, or confined, occupants cannot readily leave without the assistance of others.
- a premise or that portion of a premise where people transact business, receive personal service, or purchase food and other goods.
- None of the above
25: What type refrigerant is NOT ozone depleting?
- HFC
- CFC
- Halon
- HCFC