Topics: All categories in the pool
1: 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
- evaporator
- boiler
- compressor
- outside the machinery room
2: On a ammonia compressor, the pressure of a forced fed oil pump is changed by varying the
- opening at the pump outlet
- adjustment of the spring tension of the TXV
- opening at the pump inlet
- cooling temperature set-point
3: Liquid refrigerant flashing, or turning to vapor, in the liquid line may be due to
- liquid line that is too small
- shortage of refrigerant
- liquid line that had too high vertical lift
- All of the above
4: A self contained system
- is a unit system Group I refrigerants only
- is a complete factory made and tested system
- is a unit system Group II refrigerants only
- is any system or part of a system used to increase evaporation by expansion or vaporization
5: On a 460V motor, what is he MAXIMUM voltage that can be safely applied to it?
- 506v
- 550v
- 660v
- None of the above
6: 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
- 2,400 volts
- 240 volts
- 2.40 volts
7: What is the boiling point of refrigerant governed by?
- Condenser sub-cooling
- Compressor RPM's
- P&T relationship
- Evaporator temperature
8: Institutional occupancy is
- a premise or that portion of a premise where large numbers of people congregate and from which occupants cannot quickly vacate the space.
- a premise or that portion of a premise from which, because they are disabled, debilitated, or confined, occupants cannot readily leave without the assistance of others.
- a premise or that portion of a premise where people transact business, receive personal service, or purchase food and other goods.
- None of the above
9: A normal operating evaporator temperature of R-22 for air conditioning is typically
- 45F
- 58F
- 32F
- 55F
10: It takes how many BTU/hr to melt one pound of ice at 32F
- 970
- 180
- 144
- 212
11: How does a centrifugal compressor create the pressure differential needed to move refrigerant through the system?
- Rotating vanes
- Suction and discharge valves
- Fan-like action
- Nesting scrolls
12: The 4 basic methods of determining whether the proper amount of refrigerant is being introduced into the system are
- Buss-eye, weight, pressure, and frost line
- sight glass, weight, paper method, and frost line.
- sight glass, weight, pressure, and frost line
- sight glass, weight, pressure, and dipstick
13: What is the minimum size of the discharge pipe?
- Same size as the outlet of the relief valve
- One pipe size larger that the inlet of the relief valve
- Depends on size of manifold
- All of the above
14: Each machinery room shall contain
- a refrigerant detector located in an area where the refrigerant from a leak will concentrate
- high and low pressure controls
- smoke and fire alarms as well as three means of egress and that egress must meet 528 CMR ventilation requirements
- a toxicity detector where the presence of ammonia or lithium bromide from a leak will concentrate
15: In an air conditioning system, the unit of total heat energy content in an air/vapor mixture is
- Latent heat
- Sensible heat
- Specific heat
- Enthalpy
16: On a single phase motor, when does the start winding cut out?
- At 25% of its full rated speed
- At 50% of its full rated speed
- Start windings do no cut-out of the run cycle
- At 75% of its full rated speed
17: What is the voltage of each leg to ground of a three-phase motor with a 460v supply voltage?
- 240v
- 277v
- 208v
- 120v
18: The oil separator is always inserted in the system
- in the discharge line
- to prevent oil logging
- where it can be easily serviced
- in a cool spot
19: One watt of electrical energy in a resistive heater will provide _____ BTU/hr
- 34.15
- 6.830
- 3.415
- 16.64
20: What is the temperature that a liquid and a vapor can exist in equilibrium called?
- Dry bulb temperature
- Saturated temperature
- Wet bulb temperature
- Critical temperature
21: "R" represents ___ in the Ohm's law formula
- resistance
- capacitance
- voltage
- amperage
22: Before you change the type of refrigerant in a refrigeration system, what three things must be done?
- Place sign, check for leaks, and insulate suction line
- Make sure its compatible, notify owner, and notify AHJ.
- you can never change refrigerants
- Nothing must be done
23: The discharge relief valve is located (9.4.6)
- between the compressor and reciever
- between the compressor and the stop valve
- on top of the condensor
- between the compressor and oil separator
24: Evaporators within 18" of a heating coil must be equipped with a
- high limit control
- pressure relief device
- zone valve
- low limit control
25: The color code of a tank of ammonia is
- silver
- light green
- lavender
- white