Topics: All categories in the pool
1: Which refrigerant is lighter than air?
- R-123
- R-11
- R-717
- R-134a
2: Low pressure systems have what kind of compressor?
- Reciprocating
- Rotary
- Scroll
- Centrifugal
3: A start capacitor in series with a start winding will
- increase the amp draw of the motor
- decrease the amp draw of the motor
- increase running efficiency
- increase starting torque
4: The leaving chilled water set point for comfort cooling is typically?
- 45
- 38
- 60
- 66
5: A R-22 system running with a condensing temperature of 110F and a 40F evaporator temperature will read pressures of ____ on the high side and ____ on the low side.
- 226 psig, 68 psig
- 455 psig, 185 psig
- 257 psig, 77 psig
- 350 psig, 120 psig
6: The measurement of heat in a particular substance is
- sensible heat
- latent heat
- specific heat
- enthalpy
7: How much refrigerant can be stored in a mechanical room outside of the system?
- 330
- 100
- 150
- 200
8: Pressure vessels with an internal volume of 3 cubic feet or less
- shall use fusible plugs
- shall use pressure relief devices or fusible plugs
- do not need pressure relief protection
- shall use pressure relief devices
9: What must be done to all doors and access points in duct work going through a mechanical room?
- Must be hindged
- Must be screwed shut
- Must be sealed and gasketed
- All of the above
10: When the compressor is below the condensor
- traps are needed on the oil return line
- traps are needed on the discharge line
- traps are not needed on this type of system
- traps are needed on the suction line
11: A pressure-limiting device isn't required on a factory-sealed system containing less than ____ lbs.
- 66
- 22
- 25
- 50
12: A single pole-double throw switch uses how many wires?(excluding the ground)
- 2
- 5
- 4
- 3
13: Systems containing more than 110 pounds must have stop valves located at the
- compressor suction inlet
- compressor discharge outlet
- receiver inlet and outlet
- All of the above
14: Transformers are rated in
- volt-amps
- volts-ohms
- volts
- amps
15: Which of the following most closely represents the concentration of Li-Br in a absorption system?
- 40% Li-Br, 60% distilled water
- 40% Li-Br, 60% tap water
- 50% Li-Br, 50% tap water
- 60% Li-Br, 40% distilled water
16: On a day with low relative humidity, the two thermometers on a sling psychrometer will read
- nearly the same
- 2F difference
- a ling psychrometer doesn't have two theremometers.
- far apart or greater difference
17: What is used to check very low air pressures in air conditioning duct?
- Barometer
- Vacuum gauge
- Manometer
- Anemomter
18: Ammonia can come in contact with _______ ?
- Brass
- Aluminum
- Copper tubing
- Copper
19: Low-side system leaks in a low-pressure chiller will often result in
- nitrogen leaking out of the system.
- air being pulled into the system
- water being pulled into the system
- system refrigerant leaking from the system
20: A crankcase heater has a supplied voltage of 100 volts and is drawing 1.4 amps. What is the resistance?
- 71 ohms
- 27 ohms
- 104 ohms
- 80 ohms
21: Which of the following types of oils are hygroscopic?
- polyolester (POE)
- polyalkylene glycol (PAG)
- naphthene mineral
- both a and b
22: The main purpose of the accumulator is to
- prevent liquid slugs at the compressor
- store liquid refrigerant
- provide space for the accumulation of oil and containminants
- provide space for vapor to accumulate
23: The Board of Boilers adopts by reference
- Montreal Protocol Safety Code
- the MACS Pressure Vessel Code of Massachusetts
- the 1997 ANSI/ASHRAE Safety Code
- MSCA Code
24: RPM's of a centrifugal compressor are at approximately?
- 500
- 10,000
- 15,000
- 30,000
25: When is the only time you can leave a service container attached to a system?
- Leaking system
- Recovery
- Charging
- Both b and c