Topics: All categories in the pool
1: A micron is
- one thousandths of a millimeter
- one millonths of a centimeter
- a larger unit of measurement than Hg
- one millonths of a micrometer
2: What is the amp draw of a 40 VA transformer at 24 volts
- 1K amps
- 1.6 amps
- 1,000 amps
- 106 amps
3: What is not a requirement of a Class T machine room?
- Fire hose connected to the building fire protection system.
- Tight fitting doors
- Self-closing doors
- Automatic ventilation
4: While the system is operating, the discharge line should be
- 10-15F warmer than ambient
- room temperature
- too hot to hold by hand
- at the same temperature as the crankcase
5: If a low-pressure chiller has a low-side leak, which of the following will most likely result?
- High suction pressure and high discharge pressure.
- Low suction pressure and low discharge pressure
- Low head pressure and high suction pressure
- High head pressure and low suction pressure
6: Heat that changes the physical state of a substance without effecting a change in its temperature is known as
- lost heat
- sensible heat
- specific heat
- latent heat
7: What is a Category "M" fluid?
- Any fluid that exceeds 150 psig and has design temperatures over 366F
- A fluid which is nonflammable, nontoxic, not damaging to human tissues, does not exceed 150 psig, and the designed temperature is between -20F to 366F
- A toxic fluid, which can produce serious irreversible harm to persons on breathing or bodily content
- A typical refrigerant used on newer air conditioning and heat pump systems
8: What type of relief valve is used on a CO2 system?
- gate valve
- glove disc
- rupture disc
- fusible plug
9: R-22 is classified as a ____ refrigerant on the safety matrix.
- A-2
- B-2
- A-1
- B-1
10: Ammonia can come in contact with _______ ?
- Aluminum
- Copper tubing
- Brass
- Copper
11: How many different groups of refrigerants are there?
- 7
- 3
- 15
- 11
12: High side floats are used on centrifugal chiller systems are are considered critically charged systems.
- False
- True
- are obsolete.
- depends on the type of refrigerant being used
13: If your suction line is warmer than the room temperature, this may indicate
- below normal superheat
- plugged air filter
- an over charge
- a low charge
14: A normally operating R-410A system with a condensing temperature of 110F will have a high side pressure of around ______ psig
- 255 psig
- 365 psig
- 125 psig
- 327 psig
15: An azeotropic refrigerant is
- a mixture of two or more refrigerants that boil at about the same temperature minimizing temperature glide.
- a mixture of two or more refrigerants that boil at much different temperatures causing temperature glide
- a mixture of two or more refrigerants that boil at much different temperatures minimizing temperature glide
- none of the above
16: At higher altitudes, the boiling point of refrigerant is
- the same
- higher
- equal to the coefficient of water at 32F
- lower
17: In an air conditioning plant which an indirect low side, water is used inside of bring: the proper sequence of operating the plan is
- start the comrpessor
- reset the safety valve
- start the fan and circulating pump
- reset the expansion valve
18: How would you know if there was a loss of crankcase pressure?
- oil will foam
- oil level will rise
- oil will thin out
- oil will thicken
19: Pressure vessels of 10 cubic feet or more gross volume shall use
- at least one rupture member
- a dual pressure-relief valve if charging into the atmosphere
- at least three means of discharge and/or rupture discs
- both a and b are correct
20: A start capacitor is wired in _____ with the start windings.
- series-parallel
- parallel
- junction
- series
21: The difference between saturated liquid and saturated vapor is
- heat
- pressure
- volume
- temperature
22: Halogenated refrigerants cannot be used with what material?
- Aluminum
- Magnesium alloy
- Stainless steel
- Copper
23: When must refrigeration system covered by the code be inspected?
- Not required
- Annually and when installed
- Annually
- Upon installation
24: A direct system
- is where the refrigerant comes in contact with the space refrigerated
- is a self-contained complete factory made and tested system
- is one which encloses a separate body of evaporative refrigerant
- is on where brine is cooled & circulated to the space refrigerated
25: In a system designed for sub-zero ambient temperatures, what must be added?
- Low-ambient kit
- Infrared dye for leak identification
- Booster compressor
- Nitrogen