Topics: All categories in the pool
1: Ammonia vaporization takes place at what temperature?
- -460F
- -32F
- -28F
- -110F
2: On a centrifugal compressor, stationary diffuser vanes are needed to
- stop gas flow
- increase the clearance space
- prevent high pressure on the packing
- convert velocity energy to pressure
3: On a TXV, the purpose of an external equalizer is to?
- balance the evaporator load
- allow a greater adjustment spam
- Increase the pressure on the top of the power head diaphragm
- compensate for a pressure drop across the evaporator coil
4: A High-Probability System
- is a system highly likely to leak form a failed connection or component of such system
- is such that a leak of refrigerant from a failed connection will enter an unoccupied space
- is such that a leak of refrigerant from a failed connection will enter the occupied space
- is such that any leak will cause injury or death to anyone within a 100 square foot area
5: How are a compressor and condenser fan wired?
- series
- parallel
- parallel-series
- series-parallel
6: Can you use Ammonia in industrial applications?
- Yes, Under certain condidtions
- When mixed with R-718
- Yes, always
- No, never
7: A chilled water pump's suction gauge reads 10 psig. The discharge gauge reads 48 psig. What is the head in feet the pump is working against?
- 96
- 58
- 88
- 38
8: 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-11
- Flush with RX-11
- Flush with R-718
- Flush with ammonia
9: Refrigerant systems containing Group I refrigerants can be installed in or on public stairways.
- True
- False
10: What percentage of amperage difference is allowable phase to phase on a HVAC circuit phased to phase?
- 2%
- 1%
- 25%
- 4%
11: Booster compressors connect to the ____ side of the compressor
- oil side
- vapor
- liquid
- low side
12: The most common type of motor starter is
- part winding starter
- duel-winding starter
- across the line starter
- delts-wye starter
13: How many gallons of water per pound of ammonia do you need?
- 20
- 15
- 5
- 1
14: Sensible heat is the heat added to a substance to
- change its state
- cause evaporation
- raise its temperature
- freeze it
15: The difference between saturated liquid and saturated vapor is
- heat
- pressure
- temperature
- volume
16: Ammonia shall be discharged into ____________ or a tank containing one gallon of water for every pound of ammonia.
- the atmosphere
- a de-pressurized recovery tank with a silver top and yellow bottom
- a tank containing two pounds of a water/lithium bromide mix for every pound of ammonia
- All of the above
17: R-718 is rated unlimited for refrigeration quantity contained in a system. Why?
- Because it's a non-flammable refrigerant
- Because it's water
- Because it's cheap
- R-718 is not rated unlimited because it's a dangerous refrigerant
18: What device removes the start winding from the circuit of a split-phase motor once the motor reaches 75% of its rated load amps (RLA)?
- centrifugal switch
- printed circuit board (PCB)
- duel-voltage switch
- motor starter
19: The pressure relief device of a positive displacement compressor shall discharge in the ______________or in accordance with 9.7.8
- high side of the system
- the liquid side of the system
- the vapor side of the system
- low side of the system
20: Liquid level gauges shall have _____________ with one exception being that of the liquid level gauge bull’s eye type.
- color-coded glass to determine type of refrigerant
- moisture indicators
- automatic closing shut-off valves
- All of the above
21: What is NOT a positive displacement compressor.
- Rotary
- Scroll
- Centrifugal
- Reciprocating
22: A pressure vessel having an inside diameter of 6” or less shall be sufficient to withstand ____times the pressure of the saturation temperature of the refrigerant or ____times the critical pressure of the refrigerant, whichever is less.
- 2.5, 2.5
- 2.5, 3.0
- 3.0, 3.5
- 6.6, 6.6
23: 746 watts is equal to
- Pi
- 1 hp
- 100 hp
- 10 hp
24: The total amount of refrigerant stored in a machinery room in all containers not provided with relief valves shall not exceed
- 330 lbs
- 55 lbs
- 500 lbs
- 660 lbs
25: On a large centrifugal system, what meters the flow to the evaporator?
- Cap tube.
- TXV
- High side float
- Low side float