Topics: All categories in the pool
1: The External equalizer of a TXV compensates for
- pressure drop across the evaporator coil
- pressure within the evaporator
- pressure within the system
- pressure drop across the condenser coil
2: Halo-carbon refrigerants cannot be used with what material?
- Aluminum
- Magnesium alloy
- Copper
- Stainless Steel
3: 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
4: Heat is a form of
- power
- work
- energy
- matter
5: Gauge pressure is
- Force of pressure above that of atmosphere
- Atmospheric pressure
- Absolute pressrue
- Barometric pressure
6: In an A/C unit, dirty filters will cause
- low suction pressure
- high suction pressur
- high discharge pressure
- low oil pressure
7: A class A3 refrigerant is considered
- toxic and somewhat flammable
- non-toxic and non-flammable
- non-toxic but highly flammable
- toxic and non-flammable
8: How are safety controls wired in a circuit?
- Series
- Parallel
- Series/parallel
- Either series or parallel
9: 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
- 226 psig, 68 psig
- 257 psig, 77 psig
- 365 psig, 120 psig
- 455 psig, 185 psig.
10: By using nitrogen within a pipe during brazing operation,
- The explosion hazard is confined
- Exterior scale formation is minimized
- Discoloration is prevented
- Copper oxide formation is prevented
11: Before determining if a machinery room equipment is excluded from following Ashrae 15, you must determine how many pounds of refrigerant per _____ cubic feet?
- 10,000
- 100,000
- 100
- 1,000
12: The formula for Pure Power in a resistance circuit is
- Watts = volts X amps
- Watts X amps.
- Kw = volts X amps
- Watts X power factor
13: If the power element of an expansion valve should lose its charge the valve would
- go open
- go closed
- overfeed the evaporator
- underfeed the evaporator
14: What should never be used in pressure testing refrigeration systems?
- Oxygen
- Compressed air
- Nitrogen
- Both a and b
15: The critical temperature of a refrigerant gas occurs when
- the gas is no longer saturated
- the gas returns to a liquid
- any decrease in pressure will cause condensation
- any increase in pressure will not liquefy the gas
16: A water regulating valve opens when
- the compressor is on
- when the power is on
- the head pressure rises
- when the power is on there is an overcharge of refrigerant
17: How many different groups of refrigerants are there?
- 11
- 3
- 15
- 7
18: Atmospheric pressure is equal to
- 29.92" Hg
- 14.7 psia
- 14.7 psig
- both a & b
19: On a day with low relative humidity, the two thermometers on a sling psychrometer will read
- a ling psychrometer doesn't have two theremometers.
- nearly the same
- 2F difference
- far apart or greater difference
20: The first step in mechanical refrigeration is
- compression
- evaporation
- condensation
- expansion
21: What is an egress?
- A valve put on the low side of the system to prevent frosting
- A code violation
- An entrance or exit
- An escape route
22: _____ and its alloys are suitable for use with ammonia systems.
- Aluminum
- Magnesium
- Zinc
- Copper
23: Booster compressors, pump refrigerant into the
- heat & plate heat exchanges
- low side of the primary compressor
- receiver
- high side of the secondary compressor
24: Pressure vessels with an internal volume of 10 cubic feet or more
- shall use fusible plugs
- shall use pressure relief devices or fusible plugs
- shall use rupture discs or duel pressure relief valves
- shall use pressure relief devices
25: How are a compressor and condenser fan wired?
- parallel
- parallel-series
- series
- series-parallel