Topics: All categories in the pool
1: If air is present in an absorption chilled water appliance, which of the following will most likely occur?
- Rust can form
- System operating pressure will drop
- The Li-Br solution will become more diluted
- The Li-Br solution will become more concentrated
2: Watt's Law indicates Volts X Amps = _________.
- Ohms
- Current
- Watts
- Resistance
3: Machinery rooms must be vented to ______?
- basement
- neutralizing tank
- unoccupied spaces
- outdoors
4: If a refrigerant leaving the condenser is 94F and the condensing temperature is 105F, the subcooling is
- 9F
- 29F
- 11F
- 21F
5: What will occur if the strong solution in an absorption chiller becomes too strong?
- The machine will stop cooling and solution will crystallize
- The machine will cool excessively as the solution crystallizes.
- The machine will stop cooling and the solution will evaporate.
- The machine will cool excessively as the solution evaporates
6: RPM's of a centrifugal compressor are at approximately?
- 30,000
- 15,000
- 10,000
- 500
7: Megaohm meter's main function is
- to detect weak motor winding insulation of a refrigeration or air conditioning compressor by creating high DC voltages to the compressor
- to detect very high resistances to ground of refrigeration or air conditioning compressors
- to test very high value capacitors for large 3-phase refrigeration compressors and blower motors.
- Both a and b are correct
8: When liquid receivers are used, the liquid refrigerant shall not exceed _______percent of the volume at 90F.
- 99%
- 90%
- 75%
- 80%
9: Before you change the type of refrigerant in a refrigeration system, what three things must be done?
- nothing must be done
- place sign, check for leaks, insulate
- you can't change refrigerants
- make sure it's compatible, notify owner, notify A.H.J
10: 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
- 2,400 volts
- 24.0 volts
- 240 volts
- 2.40 volts
11: What is a high-side float?
- Located in the evaporator, is a float-type metering device that rises to reduce refrigerant flow when the liquid refrigerant level rises in the low side of the chiller
- Located in the liquid line entering the evaporator, is a float-type metering device that rises to reduce refrigerant flow when the liquid refrigerant level rises in the high side of the chiller
- An electronic-type metering device that contains a float assembly within the device which can accurately meter refrigerant into the evaporator as the load varies
- Located in the liquid line entering the evaporator, so when the refrigerant level is higher in the liquid line than the evaporator, the float rises to allow more refrigerant flow into the evaporator
12: Whoever owns/uses a refrigeration or air conditioning system covered by this code
- must notify the Department of Public Safety prior to starting the system
- shall be licensed by the Commonwealth of Massachusetts according to CMR 522
- shall make application for inspections to the Chief of Inspectors
- None of the above
13: To determine the pump size needed for an open cooling tower system, the following must be known,
- GPM and unbalanced head and friction head
- GPM and friction head
- GPM and balanced head and friction head
- GPM, pipe size, and equivalent head.
14: The ____ design is the maximum pressure for which a specific part of a refrigeration system is designed.
- high pressure
- critical pressure
- low pressure
- design pressure
15: A High-Probability System
- is such that a leak of refrigerant from a failed connection will enter the occupied space
- is such that any leak will cause injury or death to anyone within a 100 square foot area
- is a system highly likely to leak form a failed connection or component of such system
- is such that a leak of refrigerant from a failed connection will enter an unoccupied space
16: What device should be used on low-temperature freezers?
- oil separator
- discharge muffler
- high capacity TXV
- hot-gas by-pass
17: A EPR valve is installed on what type of evaporators?
- shell and tube evaporators
- low-temperature evaporators
- high-temperature evaporators
- plate evaporators
18: The color code of a tank of ammonia is
- white
- light green
- silver
- lavender
19: "R" represents ___ in the Ohm's law formula
- capacitance
- amperage
- voltage
- resistance
20: Joints in refrigeration piping must be _____ before being covered?
- Pressurized
- Insulated
- Leak tested
- Inspected
21: All serviceable components of a refrigeration system shall be provided with
- manufactures instructions on start-up procedures
- service manuals
- name plates with markings referring to pressure and temperature in accordance with ASME Boiler and Pressure Vessel Code
- safe access
22: Thermodynamics is the branch of science that deals with
- state of energy
- molecular therory
- heat energy
- energy due to motion
23: 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
24: R-718 is rated unlimited for refrigeration quantity contained in a system. Why?
- Because it's water
- Because it's a non-flammable refrigerant
- R-718 is not rated unlimited because it's a dangerous refrigerant
- Because it's cheap
25: The formula for Pure Power in a resistance circuit is
- Watts X amps.
- Watts X power factor
- Watts = volts X amps
- Kw = volts X amps