Topics: All categories in the pool
1: An electronic bridge circuit is basically a
- 24 volt control circuit
- suspension
- high voltage circuit
- Wheatstone
2: Stop valves shall not be permitted between the system and the
- condenser
- bleed valve
- relief valve
- service valve
3: The principle used in continuous type absorption systems is
- Dalton's Law
- Boyle's Law
- Ohm's Law
- Charles's Law
4: Doors communicating with outside from a mechanical room must be?
- Self-closing, approved, fire door
- Steel, approved, weather-stripped
- Self-closing, aligned, fire door
- Self-closing, wooden, fire door
5: One ton of refrigeration is defined as ______ btu/minute.
- 200
- 12,000
- 60
- 720,000
6: A “U” or “UM” marking a on a nameplate of a pressure vessels signifies compliance with Section VIII of
- the ASME Boiler and Pressure Vessel Code
- Section 11.3.1.5 ASHRAE 15 Standard
- the ANSI Standard 10.7.2
- both the ANSI Standard 10.7.2 and ASHRAE 15 Standard 11.3.1.5
7: The 522 CMR 9.00 has adopted for reference ASHRAE ____
- 10
- III
- 25
- 15
8: What type of material can't be used on the outlet of a relief valve?
- Magnesium alloy
- Stainless steel
- Copper
- PVC
9: In designing duct work, pressure and ______ need to be considered
- length
- CFM
- duct sealant used
- all of the above
10: What type of relief valve is used on a CO2 system?
- rupture disc
- fusible plug
- gate valve
- glove disc
11: Relief valves are rated in
- gallons of water per hour
- pounds of air per minute
- gallons of water per minute
- pounds of air per hour
12: How are safety controls wired in a circuit?
- Either series or parallel
- Parallel
- Series/parallel
- Series
13: What percentage of amperage difference is allowable phase to phase on a HVAC circuit phased to phase?
- 1%
- 25%
- 4%
- 2%
14: The measurement of heat in a particular substance is
- enthalpy
- specific heat
- latent heat
- sensible heat
15: What is R-22?
- CCFCM
- HFC
- Chlorodifluoromethane
- Chlorofluoromethane
16: 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
17: On a centrifugal compressor, stationary diffuser vanes are needed to
- prevent high pressure on the packing
- increase the clearance space
- convert velocity energy to pressure
- stop gas flow
18: The first step in mechanical refrigeration is
- compression
- expansion
- evaporation
- condensation
19: The External equalizer of a TXV compensates for
- pressure drop across the condenser coil
- pressure within the system
- pressure within the evaporator
- pressure drop across the evaporator coil
20: If a halide torch is used for leak detection, what color is the flame if it detects a leak?
- green
- orange
- blue
- red
21: A start capacitor is wired in _____ with the start windings.
- series
- parallel
- junction
- series-parallel
22: What will occur if the strong solution in an absorption chiller becomes too strong?
- The machine will stop cooling and the solution will evaporate.
- The machine will cool excessively as the solution evaporates
- The machine will cool excessively as the solution crystallizes.
- The machine will stop cooling and solution will crystallize
23: R-12. R-22, and R-40 are considered Group I refrigerants.
- True
- False
24: On a single phase motor, when does the start winding cut out?
- 50% of its RLA speed
- 25% of its RLA speed
- 100% of its RLA speed
- 75% of its RLA speed
25: What must be done to refrigerant pipes before being buried ?(8.10.4)
- Insulated and installed in a pipe duct (Encased)
- Certified
- Leak checked
- Classifed