Topics: All categories in the pool
1: Group A2 refrigerants have a ______ toxicity rating than Group B1 refrigerants.
- there is no Group B1 refrigerants
- higher
- lower
- the same
2: A room having machinery but no flame producing apparatus permanently installed and operated is considered a
- Class A machinery room
- Class M machinery room
- Class B machinery room
- Class T machinery room
3: R-12 is
- dichloromethane
- trichlorofluoromethane
- dichlorodifluoromethane
- dichlorofluoromethane
4: Two systems using separate refrigerants that are superimposed upon one another is called
- cascade
- single stage
- booster
- indirect
5: 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
- surge
- merge
- purge
6: R-22 falls under which safety classification?
- B-1
- A-2
- A-1
- B-2
7: Lithium-bromide, Li-Br, is best characterized as a
- salt
- soil
- sugar
- sand
8: A Low-Probability System
- is such that a leak of refrigerant from a failed connection will enter the occupied space
- is a system highly likely to leak form a failed connection or component of such system
- is such that any leak will cause injury or death to anyone within a 100 square foot area
- is such that a leak of refrigerant from a failed connection can not enter the occupied space
9: The critical temperature of a refrigerant gas occurs when
- the gas returns to a liquid
- any decrease in pressure will cause condensation
- the gas is no longer saturated
- any increase in pressure will not liquefy the gas
10: The purpose of an accumulator is to
- store excess refrigerant from the reciver
- filter out impurities from the system
- reduce friction loss to the flow of refrigerant
- assure no liquid returns to the compressor
11: Suction valve unloaders afford an effective means of
- refrigerant control
- evaporator control
- capacity control
- superheat control
12: When can 50/50 solder be used?
- in the low side
- in the high side
- liquid and suction lines
- none of the above.
13: Calculate the voltage in a series circuit when the total amperage is 10 amps and the resistors have values of: R1=12 ohms, R2=8 ohms, R3=4 ohms
- 24.0 volts
- 240 volts
- 2.40 volts
- 2,400 volts
14: Ashrae states that the equipment on a building needs to conform to adjacent buildings classifications when within ____ feet from opening and intakes.
- 50
- 20
- 75
- 15
15: A micron is
- one millonths of a micrometer
- one millonths of a centimeter
- one thousandths of a millimeter
- a larger unit of measurement than Hg
16: The difference between saturated liquid and saturated vapor is
- heat
- pressure
- volume
- temperature
17: What is the leaving chilled water set point for water chiller systems?
- 45F
- 55F
- 38F
- 66F
18: A high side float is a
- float type valve that controls the amount of refrigerant stored in the receiver
- metering device used on critically charged systems that controls the level of the liquid refrigerant in the high pressure side of the system.
- float type switch that stops the compressor when the pressure on the high side becomes too high
- float type valve that controls the crankcase oil level
19: A VRF system is a direct system
- true
- false
20: Dual-pressure relief devices should be installed on
- vessels of 10 cubic feet or more
- vessels of 3 cubic feet or less
- vessels of 3 cubic feet or more
- vessels of 10 cubic feet or less
21: Where are the three places that the discharge from an ammonia relief valve be piped?
- atmosphere, tank containing water, where the A.H.J. indicates
- underground, into drain, into mechanical room
- to chemical neutralizing tank only
- none of the above
22: Low pressure chiller systems use what type of compressor?
- Centrifugal
- Scroll
- Reciprocating
- Screw
23: R-22 is classified as a ____ refrigerant on the safety matrix.
- A-2
- B-1
- B-2
- A-1
24: It takes how many BTU/hr to melt one pound of ice at 32F
- 970
- 212
- 144
- 180
25: If the suction pressure is low and the evaporator temperature high, the cause will be a?
- starved evaporator
- compressor suction valve stuck open
- too small evaporator
- overcharged