Topics: All categories in the pool
1: 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
- 365 psig, 120 psig
- 257 psig, 77 psig
- 226 psig, 68 psig
- 455 psig, 185 psig.
2: _____ alloys shall not be used in contact with an halogenated refrigerants.
- Copper
- Zinc
- Nickel
- Magnesium
3: 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.
- 3.0, 3.5
- 2.5, 3.0
- 2.5, 2.5
- 6.6, 6.6
4: On cooling towers, what causes the condenser water to drop
- ambient temperatures
- sensible heat
- evaporation of the water droplets
- tower fans
5: What type of voltage causes the winding in a potential relay to open?
- BEMF (Back Electro-Motive Force)
- 24V control voltage from the thermostat
- 120V line voltage
- None of the above
6: A VRF system is a direct system
- true
- false
7: The proper location for an oil separator is between the
- receiver and metering device
- evaporator and compressor
- condenser and receiver
- compressor and condenser
8: A positive displacement compressor is
- a compressor in which the increase in pressure is attained by changing the internal volume of the compression chamber
- is a reciprocating type compressor with 2 or more pistons
- where the compressor's suction pressure and the compressor;s discharge pressure is more than 50 PSI
- a compressor in which the increase in pressure is attained by changing the internal pressure of the compression chamber
9: If the compression ratio on a centrifugal compressor rises too high, the compressor will stop pumping and make a loud sound commonly referred to as a
- purge
- splurge
- merge
- surge
10: R-717 is
- ammonia
- trichloromethane
- water
- carbon dioxide
11: What is the typical air conditioning operating pressures for R-22?
- 60 psi suction 210 psi discharge
- 25 psi suction 125 psi discharge
- 105 psi suction 340 psi discharge
- None of the above
12: Refrigerant piping crossing an open space that affords passageway in any building shall not be less than _____ feet above the floor unless piping is located against the ceiling.
- 7.00'
- 7.25'
- 9.00'
- 8'4"
13: There can be no airflow from an occupied space through a machine room unless what?
- System is high velocity
- System is ducted and sealed
- Duct is not located in the ceiling
- None of the above.
14: What is the state of the refrigerant leaving the evaporator?
- a high temperature subcooled liquid
- a high temperature superheated vapor
- a low temperature subcooled liquid
- low temperature superheated vapor
15: Give an example of a secondary coolant?
- R-12
- R-717
- R-410A
- R-718
16: If the suction pressure is low and the evaporator temperature high, the cause will be a?
- overcharged
- compressor suction valve stuck open
- starved evaporator
- too small evaporator
17: Gauge pressure is
- what a gauge reads when checking pressures on a chilled water system.
- force of pressure above that of atmospheric
- atmospheric pressure
- absolute pressure
18: Pressure relief valves shall be marked with the data from
- Section I Division VIII of ASME Boiler & Pressure Code
- Section VIII Division of the ASME Boiler & Pressure Code
- Section XIII Division of the ASME Boiler & Pressure Code
- Section IV Division of the ASME Boiler & Pressure Code
19: Name an HCFC refrigerant(s):
- R-22
- R-123
- R-11
- both a & b
20: A restaurant is classified as a
- mixed occupancy
- commercial occupancy
- public assembly occupancy
- large mercantile occupancy
21: Adjusting the spring pressure on a TXV
- changes superheat
- changes subcooling
- adjusts the bulb charge
- makes no difference
22: A tachometer is an instrument used to measure
- speed
- RPM
- static pressure
- air velocity
23: When using nitrogen for brazing, the pressure should be:
- Slightly below atmospheric
- 125 psig
- 50-100 psig
- Very low
24: Ammonia belongs to Group
- B-2
- A-2
- A-1
- B-1
25: A compressor in which the increase in vapor pressure is attained without changing the internal volume of the compression chamber is called
- non-positive displacement compressor
- non-volumetric displacement compressor
- neutral chamber-type compressor
- negative displacement compressor