Topics: All categories in the pool
1: On a ammonia compressor, the pressure of a forced fed oil pump is changed by varying the
- cooling temperature set-point
- adjustment of the spring tension of the TXV
- opening at the pump inlet
- opening at the pump outlet
2: The color code of a tank of ammonia is
- light green
- white
- silver
- lavender
3: Which refrigerant(s) is an HFC?
- R-22
- R-410A
- R-502
- All of the above
4: A chiller entering and leaving temperature difference is?
- 5 degrees F
- 20 degrees F
- 50 degrees F
- 10 degrees F
5: What device measures the specific gravity of a substance?
- Hydrometer
- Manometer
- Hygrometer
- Thermometer
6: What refrigerant is an inorganic compound?
- R-410A
- R-132A
- R-22
- Ammonia
7: Ashrae states that the equipment on a building needs to conform to adjacent buildings classifications when within ____ feet from opening and intakes.
- 50
- 15
- 20
- 75
8: Booster compressors connect to the ____ side of the compressor
- oil side
- vapor
- liquid
- low side
9: 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
10: The principle used in continuous type absorption systems is
- Charles's Law
- Ohm's Law
- Boyle's Law
- Dalton's Law
11: An oil pressure safety switch should be set at
- 5 to 10 psi below low side pressure
- 5 to 10 psi above low side pressure
- 10 to 15 psi below low side pressure
- 10-15 psi above low side pressure
12: A rule of thumb in air conditioning is ____ CFM per ton?
- 600
- 100
- 400
- 500
13: Ammonia is under what safety classification?
- A3
- B2
- B3
- B1
14: 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
- boost voltage
- pick-up voltage
- lift voltage
- run voltage
15: 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
16: 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
- 455 psig, 185 psig
- 257 psig, 77 psig
- 350 psig, 120 psig
17: If a liquid receiver is designed to receive the refrigerant charge during a pumpdown procedure, it shall have the capacity to
- release the charge when the pressure exceeds 310 psig or higher
- receive the pumpdown charge
- hold up to 110% of the pumpdown charge
- Pumpdown procedures are not allowed with systems containing liquid recievers
18: Class T machine room
- shall have refrigerant leak detecting systems installed inside and outside the room
- shall have remote controls to stop the action of the refrigerant compressor
- shall include closets used for setting equipment
- has no flame producing apparatus permanently installed
19: When using nitrogen for brazing, the pressure should be:
- 50-100 psig
- Slightly below atmospheric
- Very low
- 125 psig
20: Pressure vessels having an inside diameter of 6” or less shall be protected by
- Pressure vessels having an inside diameter of 6” or less need no such protection unless otherwise specified
- a pressure relief device
- either a fusible plug or a pressure relief device
- a fusible plug
21: R-123 belongs to Group
- B-1
- B-2
- A-3
- B-3
22: Emergency shutdown procedures, including precautions to be observed in case of a breakdown or leak over 55 lbs of refrigerant charge, shall be displayed on a conspicuous card located as near as possible to the
- boiler
- outside the machinery room
- compressor
- evaporator
23: Which is considered the more efficient condenser?
- water cooled
- fan cooled
- spray cooled
- air cooled
24: The heat picked up in the evaporator must equal to
- the heat giving by the condenser
- the heat lost by the medium being cooled
- the heat gained by the condenser
- the heat of compression
25: 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