Topics: All categories in the pool
1: Control systems can be classified by
- tonnage of system
- safety
- economy of operation
- source of power
2: 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?
- 25 uf
- 20 uf
- 40 uf
- 15 uf
3: 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
4: Which refrigerant replaced R-12?
- R-410A
- R-134A
- R-407A
- R-22
5: What type of oil is used in R-410A systems?
- naphthene
- mineral oil
- polyolester (POE)
- polyalkylene glycol (PAG)
6: Where is an EPR valve located on a multi-evaporator system?
- Suction line of the warmest evaporator
- Suction line at the compressor
- Suction line prior to the accumulator of the lowest temperature system
- Suction line of the coolest evaporator
7: 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
8: Refrigeration piping before being buried shall be
- leak tested
- encased in pipe duct
- pressure tested
- All of the above
9: R-12 is
- trichlorofluoromethane
- dichlorodifluoromethane
- dichloromethane
- dichlorofluoromethane
10: If the spring is adjusted to increase the superheat, this new setting will
- lengthen the frost line
- have no effect on the frost line
- shorten the frost line
- allow more liquid into the evaporator
11: Liquid level gauge glasses shall have automatic closing shut off valves, except Bull's eye or reflex type.
- True
- False
12: If air is present in an absorption chilled water appliance, which of the following will most likely occur?
- Rust can form
- The Li-Br solution will become more concentrated
- System operating pressure will drop
- The Li-Br solution will become more diluted
13: Volts x amps equals
- Ohms Law
- Watts
- Impedance
- Inductance
14: How many groups of refrigerants are there?
- 7
- 5
- 3
- 1
15: When using nitrogen for brazing, the pressure should be:
- Very low
- 50-100 psig
- Slightly below atmospheric
- 125 psig
16: Watt's Law indicates Volts X Amps = _________.
- Resistance
- Ohms
- Current
- Watts
17: The 522 CMR 9.00 has adopted for reference ASHRAE ____
- 15
- 25
- 10
- III
18: 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
19: A total of all group A-2,B-2, A-3, and B-3 refrigerants shall not exceed ____ lb in the occupied areas and machinery rooms of institutional occupancies.
- 100
- 50
- 350
- 550
20: According to the 522 CMR Board of Boilers, refrigerant detectors, alarms, and the refrigeration mechanical room ventilating systems shall be tested
- annually
- bi-annually
- quarterly
- regularly
21: What percentage of amperage difference is allowable phase to phase on a HVAC circuit phased to phase?
- 2%
- 1%
- 25%
- 4%
22: A multi-evaporator refrigeration system uses what type of valve to maintain evaporating temperatures?
- EEV
- EPR valve
- Solenoid valve
- CPR valve
23: R-12. R-22, and R-40 are considered Group I refrigerants.
- True
- False
24: A high side float is a
- metering device used on critically charged systems that controls the level of the liquid refrigerant in the high pressure side of the system.
- float type valve that controls the amount of refrigerant stored in the receiver
- float type valve that controls the crankcase oil level
- float type switch that stops the compressor when the pressure on the high side becomes too high
25: Fractionation occurs when
- the pressures decreases as the heat load decreases
- the pressures increase as the heat load increases
- when a fraction of refrigerant is added as the full charge
- some of the blended refrigerant evaporates or condenses before the rest of the blend