Topics: All categories in the pool
1: A tachometer is an instrument used to measure
- static pressure
- speed
- RPM
- air velocity
2: How many flammability classifications are refrigerants in?
- 7
- 2
- 3
- 5
3: How do you find net oil pressure on a compressor?
- discharge pressure - suction pressure
- gross oil pressure - suction pressure
- gross oil pressure - discharge pressure
- all of the above
4: Brazed joints melt at temperatures above
- 1,200F
- 800F
- 1,000F
- 500F
5: Viscosity is
- measure of weight
- the coefficient of external friction
- the ability of oil to flow
- a measure of heat content
6: Pressure limiting devices are not required for systems containing less then ________ refrigerants.
- 6.6 lbs
- 44 lbs
- 13.9 lbs
- 22 lbs
7: What kind of system uses two different refrigerants in separate systems dependent on each other?
- Simple
- Cascade
- Low pressure
- R-414B
8: Pairs of mating stop valves that allow sections of a system to be joined before opening these valves or separated after closing them are
- companion or block valves
- king valves
- gate or globe valves
- ball valves
9: A chilled water pump suction gauge reads 10 psig. Discharge gauge reads 48 psig. The head in feet of the pump is working against
- 108
- 88
- 116
- 38
10: On an air cooled condenser, if the ambient air is 35F and dropping, what's its effect to the condensor?
- it would make the condenser more efficient
- it would make the condenser less efficient
- it would cause the condenser to sweat
- it would have no effect on the condenser
11: How does a centrifugal compressor create the pressure differential needed to move refrigerant through the system?
- Suction and discharge valves
- Fan-like action
- Nesting scrolls
- Rotating vanes
12: A chiller entering and leaving temperature difference is?
- 50 degrees F
- 20 degrees F
- 10 degrees F
- 5 degrees F
13: In an A/C unit, dirty filters will cause
- low suction pressure
- high discharge pressure
- low oil pressure
- high suction pressur
14: Clearance volume
- affects compressor capacity
- varies depending on compressor speed
- is the same on all compressors
- has no effect on compressor capacity
15: The ASHRAE Standard 34 requires what type of alarm for equipment rooms using HCFC-123?
- A group sensing
- refrigerant sensing
- CO Sensing
- phosgene gas sening
16: Foaming of oil in a compressor is most likely to occur
- when there is insufficient air across the condenser(i.e., dirty coil)
- when the evaporator temperatures are below 32F
- at start-up
- when ambient temperature are low
17: Lithium-bromide, Li-Br, is best characterized as a
- sugar
- soil
- sand
- salt
18: Atmospheric pressure is equal to
- 29.92" Hg
- 14.7 psia
- 14.7 psig
- both a & b
19: The certificate of inspection
- shall be authorized by a notarized insurance company
- shall be posted and protected from dirt, water, and other elements
- shall be $20 and an additional fee of $1 for each tone above 20 tons
- shall be posted on the compressor shell or electrical panel at the unit
20: Indirect systems using Group II refrigerants
- shall be used in refrigeration system in excess of 1,000 lbs
- shall be used in refrigeration system less than 1,000 lbs
- shall be used for mechanical equipment only
- shall have all refrigerant containing parts except piping, installed in a Class T machine room
21: Liquid level gauge glasses shall have automatic closing shut off valves, except Bull's eye or reflex type.
- True
- False
22: What is the minimum height refrigeration piping should be placed against walls?
- Ceiling height
- 72"
- 7.25'
- 6'
23: High side floats are used on centrifugal chiller systems are are considered critically charged systems.
- are obsolete.
- depends on the type of refrigerant being used
- True
- False
24: The location of the thermal bulb for the TXV on the evaporator effects
- both the pressure and temperature in the feeler bulb
- the amount of superheat required to operate the TXV
- the amount of liquid in the evaporator
- the amount of gas in the evaporator
25: On a ammonia compressor, the pressure of a forced fed oil pump is changed by varying the
- cooling temperature set-point
- opening at the pump outlet
- opening at the pump inlet
- adjustment of the spring tension of the TXV