Topics: All categories in the pool
1: 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
2: 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
3: In a properly balanced system with valves open and properly adjusted, if the suction line is warm to the touch, its because of
- not enough oil in the system
- oil in evaporator
- moisture in the system
- low head pressure
4: Booster compressors, pump refrigerant into the
- low side of the primary compressor
- receiver
- high side of the secondary compressor
- heat & plate heat exchanges
5: When an A/C system is excessively low on refrigerant
- it can become contaminated with water
- there can be nuisance trip outs
- the suction line may be too hot to touch
- All of the above
6: What is the refrigerant chlorodifluoromethane?
- R-134a
- R-22
- R-12
- R-123
7: What kind of system uses two different refrigerants in separate systems dependent on each other?
- Cascade
- Low pressure
- R-414B
- Simple
8: What type of relief valve is used on a CO2 system?
- glove disc
- rupture disc
- gate valve
- fusible plug
9: If the power element of an expansion valve should lose its charge the valve would
- overfeed the evaporator
- underfeed the evaporator
- go open
- go closed
10: All machine rooms must be outfitted with a detector that _______?
- activates an audible alarm
- activates a visual alarm
- starts the ventilation system
- All of the above
11: At higher altitudes, the boiling point of refrigerant is
- higher
- equal to the coefficient of water at 32F
- the same
- lower
12: A halide torch is most useful with a freon compression system
- to detect refrigeration leaks in piping joints
- to remove from from TXV's and evaporator coils
- to sweat flanges on the refrigeration piping
- to release a sticking valve
13: 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
- pick-up voltage
- run voltage
- boost voltage
- lift voltage
14: A machine room with a refrigerant system using ammonia shall
- be provided with a continuously operated ventilation system
- be considered a non-hazardous location in accordance with National Electrical code
- have no flame producing apparatus permanently installed and operated
- All of the above
15: Low-side system leaks in a low-pressure chiller will often result in
- water being pulled into the system
- nitrogen leaking out of the system.
- system refrigerant leaking from the system
- air being pulled into the system
16: What is NOT a positive displacement compressor.
- Centrifugal
- Rotary
- Reciprocating
- Scroll
17: Group A3 refrigerants have a ______ flammability rating than Group B1 refrigerants
- higher
- lower
- there is no Group B1 refrigerants
- the same
18: 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.
19: 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
- 50
- 24
20: The two float-type metering devices are the
- high-side float and the low-side float
- vapor float and the low-side float.
- liquid float and the low-side float
- liquid float and the vapor float
21: Halogen refrigerants are corrosive to which type of metal?
- stainless steel
- black iron
- copper
- magnesium
22: Which is considered the more efficient condenser?
- fan cooled
- water cooled
- air cooled
- spray cooled
23: A tachometer is an instrument used to measure
- RPM
- static pressure
- air velocity
- speed
24: Who authorizes changes to the safety codes?
- Contractor who last serviced the system.
- Person who pulled the permit
- Board of Boilers
- Person in charge of the facility
25: A start capacitor in series with a start winding will
- decrease the amp draw of the motor
- increase running efficiency
- increase starting torque
- increase the amp draw of the motor