Topics: All categories in the pool
1: "I" represents ____ in the Ohm's law formula.
- voltage.
- resistance
- amperage
- capacitance
2: What is the minimum size wire you can use on a 30 amp circuit?
- 14 AWG
- 12 AWG
- 10 AWG
- 16 AWG
3: The purpose of an accumulator is to
- store excess refrigerant from the reciver
- reduce friction loss to the flow of refrigerant
- assure no liquid returns to the compressor
- filter out impurities from the system
4: Suction valve unloaders afford an effective means of
- superheat control
- capacity control
- refrigerant control
- evaporator control
5: A R-410A system running with a condensing temperature of 110F and 50F evaporator temperature will read pressures of ___ on the high side and ___ on the low side
- 226 psig, 68 psig
- 455 psig, 185 psig.
- 365 psig, 120 psig
- 257 psig, 77 psig
6: The measurement of heat in a particular substance is
- enthalpy
- sensible heat
- latent heat
- specific heat
7: The gauge thickness required on a CO2 tank construction is
- 5/16"
- 3/32"
- 1/16"
- 1/8"
8: What percentage of amperage difference is allowable phase to phase on a HVAC circuit phased to phase?
- 1%
- 25%
- 2%
- 4%
9: Setting a pressure relief device shall not exceed ___ of the design pressure
- 100%
- 75%
- 80%
- 90%
10: A EPR valve is installed on what type of evaporators?
- high-temperature evaporators
- plate evaporators
- shell and tube evaporators
- low-temperature evaporators
11: The color code of a tank of ammonia is
- lavender
- silver
- white
- light green
12: What is the temperature that a liquid and a vapor can exist in equilibrium called?
- Wet bulb temperature
- Critical temperature
- Dry bulb temperature
- Saturated temperature
13: Low pressure systems have what kind of compressor?
- Centrifugal
- Scroll
- Reciprocating
- Rotary
14: 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
15: How far from the window does a relief valve need to be according to ASHRAE-15?
- At least 20'
- At least 30'
- There is no minimum for relief valve and windows.
- At least 40'
16: Which of the following most closely represents the concentration of Li-Br in a absorption system?
- 40% Li-Br, 60% tap water
- 60% Li-Br, 40% distilled water
- 50% Li-Br, 50% tap water
- 40% Li-Br, 60% distilled water
17: What is the maximum voltage range allowed on an electrical circuit?
- 10%
- 5%
- 15%
- 20%
18: It takes how many BTU/hr to melt one pound of ice at 32F
- 180
- 212
- 144
- 970
19: What is the leaving chilled water set point for water chiller systems?
- 38F
- 66F
- 45F
- 55F
20: Two capacitors are wired in parallel. One capacitor has a value of 15uf. The other has a value of 25uf. What is the total value supplied?
- 15 uf
- 20 uf
- 25 uf
- 40 uf
21: The critical temperature of a refrigerant gas occurs when
- any increase in pressure will not liquefy the gas
- the gas returns to a liquid
- any decrease in pressure will cause condensation
- the gas is no longer saturated
22: A solder joint melts at temperatures of
- 400F to 800F
- 600F to 900F
- less than 400F
- 1,200F to 1,500F
23: All machine rooms must be outfitted with a detector that _______?
- activates an audible alarm
- activates a visual alarm
- starts the ventilation system
- All of the above
24: R-12. R-22, and R-40 are considered Group I refrigerants.
- True
- False
25: A direct system
- is one which encloses a separate body of evaporative refrigerant
- is on where brine is cooled & circulated to the space refrigerated
- is where the refrigerant comes in contact with the space refrigerated
- is a self-contained complete factory made and tested system