Topics: All categories in the pool
1: Adjusting the spring pressure on a TXV
- changes subcooling
- adjusts the bulb charge
- changes superheat
- makes no difference
2: Which refrigerant was still able to be vented to the atmosphere after July 1, 1992?
- R-113
- R-12
- R-11
- R-22
3: Atmospheric pressure is equal to
- 29.92" Hg
- 14.7 psia
- 14.7 psig
- both a & b
4: On a TXV, the purpose of an external equalizer is to?
- compensate for a pressure drop across the evaporator coil
- Increase the pressure on the top of the power head diaphragm
- allow a greater adjustment spam
- balance the evaporator load
5: Which winding have the most turns?
- they have equal amount of turns
- run
- depends on the motor phase
- Start
6: A 3-cubic foot receiver must have what type of relief valve?
- fusible plug
- relief valve
- rupture device
- none of the above
7: Halo-carbon refrigerants cannot be used with what material?
- Magnesium alloy
- Stainless Steel
- Aluminum
- Copper
8: Indirect systems using Group II refrigerants
- shall be used for mechanical equipment only
- shall have all refrigerant containing parts except piping, installed in a Class T machine room
- shall be used in refrigeration system less than 1,000 lbs
- shall be used in refrigeration system in excess of 1,000 lbs
9: A restaurant is classified as a
- large mercantile occupancy
- commercial occupancy
- public assembly occupancy
- mixed occupancy
10: When using nitrogen for brazing, the pressure should be:
- 50-100 psig
- Slightly below atmospheric
- 125 psig
- Very low
11: Which refrigerant replaced R-12?
- R-410A
- R-407A
- R-134A
- R-22
12: An oil pressure safety switch should be set at
- 5 to 10 psi above low side pressure
- 10-15 psi above low side pressure
- 5 to 10 psi below low side pressure
- 10 to 15 psi below low side pressure
13: Which of the following controllers would you expect to be most sensitive to temperature changes?
- low voltage t-stat
- immersion controller
- aquastat
- line voltage t-stat
14: When must refrigeration system covered by the code be inspected?
- Annually
- Not required
- Upon installation
- Annually and when installed
15: The main cause of enacting the "no vending rule" of July 1st 1992 was
- global warming potential
- ozone depletion
- both a & b
- None of the above
16: When should a relief valve start to function?
- Before the purge station discharges
- 10 psi before it's set pressure
- Two times it's working pressure
- At it's set pressure
17: Transformers are rated in
- amps
- volts
- volt-amps
- volts-ohms
18: What percentage of amperage difference is allowable phase to phase on a HVAC circuit phased to phase?
- 1%
- 4%
- 2%
- 25%
19: What is potential measured in?
- Amps
- Ohms
- Volts
- Henrys
20: Halogenated refrigerants cannot be used with what material?
- Magnesium alloy
- Aluminum
- Copper
- Stainless steel
21: What was the main reason for enacting the no venting rule of July 1, 1992?
- Ozone depletion
- Green house effect
- Global warming potential
- All of the above
22: Which of the following types of oils are hygroscopic?
- polyolester (POE)
- polyalkylene glycol (PAG)
- naphthene mineral
- both a and b
23: Pressure limiting devices are not required for systems containing less then ________ refrigerants.
- 22 lbs
- 13.9 lbs
- 44 lbs
- 6.6 lbs
24: When releasing a hydrogenated hydrocarbon refrigerant to the atmosphere, ample ventilation must be provided and
- the owner shall be informed
- explosion precautions must be taken
- gas masks must be worn
- no flames shall be permitted
25: What does “ultimate strength” mean?
- Design strength of the vessel or piping in a refrigeration system
- Stress at which rupture will occur
- Highest or design pressure allowed inside a machinery room
- None of the above