Topics: All categories in the pool
1: A compressor in which the increase in vapor pressure is attained without changing the internal volume of the compression chamber is called
- negative displacement compressor
- non-positive displacement compressor
- neutral chamber-type compressor
- non-volumetric displacement compressor
2: Class T machine room
- shall include closets used for setting equipment
- shall have refrigerant leak detecting systems installed inside and outside the room
- shall have remote controls to stop the action of the refrigerant compressor
- has no flame producing apparatus permanently installed
3: The 522 CMR 9.00 has adopted for reference ASHRAE ____
- 25
- III
- 10
- 15
4: What should not (and can not) be located between a pressure imposing device and a pressure-limiting device?
- Stop valve
- Moisture indicator
- Muffler
- Foot valve
5: "P" represents ______ in the Watt's law formula
- watts
- reactance
- amperage
- voltage
6: Secondary refrigerants are usually
- Prestone anti-freeze
- alcohol
- expensive
- water or brine
7: Liquid level gauges must be provided with what?
- A relief valve
- A red line
- Automatic shut-offs
- A low level mark
8: R-718 is rated unlimited for refrigeration quantity contained in a system. Why?
- R-718 is not rated unlimited because it's a dangerous refrigerant
- Because it's a non-flammable refrigerant
- Because it's cheap
- Because it's water
9: 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
10: How is bring measured?
- hydrometer
- manometer
- hygrometer
- anemometer
11: It takes how many BTU's of latent heat/hr to boil 1 lbs of water into steam?
- 12,000 BTU
- 970 BTU
- 24,000 BTU
- 144 BTU
12: A mercury bulb controller is not recommended for
- low voltage use
- use where vibration is severe
- line voltage use
- line or low voltage use
13: A motor starter contains a thermal overload and a
- solenoid
- 3-way relay
- transformer
- contactor
14: E = I X R is
- Ohms Law
- Amps Law
- Impedance Law
- Watts Law
15: Horizontal piping should be run level.
- True
- Yes, if the condenser is located above the evaporator
- No, unless the supervisor on the job says so.
- False
16: Can a R22 line set be reused for a 410A system and if it can be reused, what must be done to it?
- Flush with R-718
- Flush with R-11
- Flush with RX-11
- Flush with ammonia
17: 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.
- Nothing must be done
- you can never change refrigerants
18: R-12 is
- dichlorofluoromethane
- dichlorodifluoromethane
- dichloromethane
- trichlorofluoromethane
19: A “U” or “UM” marking a on a nameplate of a pressure vessels signifies compliance with Section VIII of
- the ASME Boiler and Pressure Vessel Code
- Section 11.3.1.5 ASHRAE 15 Standard
- the ANSI Standard 10.7.2
- both the ANSI Standard 10.7.2 and ASHRAE 15 Standard 11.3.1.5
20: The formula for Pure Power in a resistance circuit is
- Watts = volts X amps
- Kw = volts X amps
- Watts X power factor
- Watts X amps.
21: On a centrifugal compressor, stationary diffuser vanes are needed to
- increase the clearance space
- convert velocity energy to pressure
- prevent high pressure on the packing
- stop gas flow
22: What would be the classification for Stop & Shop grocery store?
- Industrial
- Large mercantile
- Place of assembly
- Instituional
23: What is a Category "D" fluid?
- A fluid which is nonflammable, nontoxic, not damaging to human tissues, does not exceed 150 psig, and design temperature is between -20F to 366F
- A typical refrigerant used on newer air conditioning and heat pump ssytems
- Any fluid that exceeds 150 psig and has design temperature of over 366F
- A toxic fluid, which can produce serious irreversible harm to persons on breathing or bodily contact
24: Doors communicating with outside from a mechanical room must be?
- Self-closing, aligned, fire door
- Self-closing, approved, fire door
- Steel, approved, weather-stripped
- Self-closing, wooden, fire door
25: In an electrical circuit, what is potential measured in?
- Ohms
- Volts
- Amps
- Herys