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What is the function of a heat recovery ventilator (HRV)?
Removing stagnant air from the structure at a controlled rate
Introducing outside air into the structure at the same rate at which air is removed
Recovering heat from the air being removed and transferring this heat to the air entering the structure
All of these are true.
All of these are true.
The humidifier should exhaust directly onto air filters and electronic air cleaners.
True
False
False
The ___________ of air is the measure of heat content in Btu per pound of air.
a. relative humidity
b. temperature
c. enthalpy
d. atmospheric pressure
c. enthalpy
The reading from a wet-bulb thermometer ____.
a. is the same as the wet-bulb depression
b. is the saturation pressure
c. takes into account the moisture content of the air
d. is always higher than the dry-bulb temperature
c. takes into account the moisture content of the air
The term air conditioning refers to __________.
a. ventilation and filtration of air
b. a refrigeration process that is applied to comfort cooling
c. circulation of air through a closed space
d. electrically powered comfort cooling
b. a refrigeration process that is applied to comfort cooling
A supplemental photocatalytic oxidation filter (PCO) is often included with ____________________ air purifiers.
a. activated charcoal
b. UV
c. electrostatic
d. energy recovery
b. UV
Humidification generally relates to the process of causing water to ____ into the air.
a. condense
b. evaporate
c. be ionized
d. be filtered
b. evaporate
Infiltration is the term used when referring to the air entering a structure ____.
The density of water is ____.
a. 61.3 lb/ft3
b. 62.0 lb/ft3
c. 62.4 lb/ft2
d. 62.4 lb/ft3
d. 62.4 lb/ft3
The supply duct portion of an air handling system needs to be insulated when run through an unconditioned space.
a. True
b. False
a. True
Which factor should be considered when determining the size of humidifier needed?
a. Lowest outdoor temperature
b. Quality of insulation
c. Number of air changes
d. All of these should be considered.
d. All of these should be considered.
In the ionizing section of an electronic air cleaner, the particles in the air are ____________.
a. vacuumed out
b. given a positive charge
c. filtered through charcoal
d. broken down by UV light
b. given a positive charge
When fresh air is introduced through the air handling system, the process is called ___________.
a. air conditioning
b. purification
c. infiltration
d. ventilation
d. ventilation
If the dry-bulb temperature is 93°F and the wet-bulb temperature is 60°F, what is the specific volume of the air?
a. 14.0 ft3/lb
b. 14.0 lb/ft3
c. 12.0 lb/ft3
d. 12.0 ft3/lb
a. 14.0 ft3/lb
If a structure has no attic, there should be sufficient insulation in the roof to minimize the heat gain in the occupied space.
a. True
b. False
a. True
ASHRAE Standard 62.1 is generally used by HVAC engineers and technicians to determine acceptable ________.
a. indoor air quality
b. pesticide levels
c. relative humidity
d. sizing for humidifiers
a. indoor air quality
The steps to aggressively controlling the contamination of indoor air would involve ____.
A small amount of air is introduced from the outside into the conditioner to keep the air from becoming ____.
a. too humid
b. superheated
c. oxygen-starved and stagnant
d. too dry
c. oxygen-starved and stagnant
The human body is comfortable when the heat produced in the body is equal to the heat lost to the surroundings.
a. True
b. False
a. True
Compared to other types of compressors, reciprocating compressors are _______.
a. discharge-cooled rather than suction-cooled
b. more common in newly manufacturing systems
c. more efficient
d. less efficient
d. less efficient
Carbon monoxide is a poisonous gas produced by _____.
a. incomplete combustion in oil- or gas-fired appliances
b. excess combustion air
c. incomplete mixing of oxygen and fuel
d. All of these are true.
d. All of these are true.
What level of mold contamination corresponds to areas from 10 to 30 ft2?
a. Level I
b. Level II
c. Level III
d. Level IV
b. Level II
Air consists of approximately ____________, and 1% other gases.
Refrigerant enters the condenser as a ________ and leaves the condenser as a _______.
a. high-pressure, high-temperature vapor; high-pressure, high-temperature subcooled liquid
b. high-pressure, high-temperature subcooled liquid; high-pressure, high-temperature vapor
c. high-pressure, high-temperature vapor; low-pressure, low-temperature subcooled liquid
d. low-pressure, low-temperature liquid; high-pressure, high-temperature subcooled vapor
a. high-pressure, high-temperature vapor; high-pressure, high-temperature subcooled liquid
When exposed to salt air, ____ should be used for the screws to secure the sheet metal of cabinets of air conditioning equipment.
a. copper
b. stainless steel
c. iron
d. tin
b. stainless steel
People who are active and spend a great deal of time outdoors are more likely to experience the effects of pollution.
a. True
b. False
b. False
The controller for a humidifier, a humidistat, has an element that is ____-sensitive.
a. moisture
b. light
c. infrared
d. temperature
a. moisture
If the wet-bulb and dry-bulb temperatures are both 80°F, what is the humidity?
a. 0%
b. 35%
c. 70%
d. 100%
d. 100%
A homeowner plans to build a house in Las Vegas, Nevada, in the middle of the desert. It would be in their best interest to lower the solar load by locating most of the windows on the ____ sides of the house.
a. north and east
b. east and west
c. north and south
d. south and west
c. north and south
In a split-system air-conditioning system, the liquid line connects the outlet of the ______ at the outdoor unit to the inlet of the ______at the indoor unit.
a. condenser; metering device
b. evaporator; compressor
c. compressor; evaporator
d. condenser; evaporator
a. condenser; metering device
Because humidifiers use water, the evaporative surfaces and water reservoir must be cleaned and sanitized regularly to prevent the distribution of ____ by the moving airstream.
a. fungi
b. bacteria
c. algae
d. All of these are true.
d. All of these are true.
Compared to a filtering system with a MERV rating of 7, a system with a MERV rating of 13 would have a ________efficiency and cause a ________ pressure drop.
a. greater; smaller
b. greater; larger
c. lower; larger
d. lower; smaller
b. greater; larger
The rate at which water will evaporate from the wick on the wet-bulb thermometer is determined by the moisture content of the surrounding air.
True
False
True
In reciprocating compressors used in air conditioning, the motor is mainly cooled by ____.
a. air over the shell of the assembly only
b. discharge gas from the compressor only
c. suction gas returning to the compressor
d. air over the shell of the assembly and suction gas returning to the compressor
d. air over the shell of the assembly and suction gas returning to the compressor
The package air-conditioning system is ____ than the split system because it is completely factory assembled and charged with refrigerant.
a. less efficient
b. slightly less efficient
c. slightly more efficient
d. more efficient
d. more efficient
Which action is the first step when cleaning an air distribution system?
a. Place a filter on the inlet to the return duct system.
b. Exhaust particles outdoors using the vacuum system.
c. Reseal and reinsulate access holes.
d. Inspect the system for asbestos.
d. Inspect the system for asbestos.
The closer the wet-bulb and dry-bulb temperatures are to each other, the higher the ____________.
a. relative humidity
b. dew point temperature
c. saturation point
d. atmospheric pressure
a. relative humidity
The best way to reduce the cost of heating a home in the winter while maintaining comfortable conditions is by ______ the humidity level and _________ the thermostat setting.
a. raising; lowering
b. lowering; lowering
c. lowering; raising
d. raising; raising
a. raising; lowering
Air-conditioning equipment will perform at its best efficiency when running at full load.
a. True
b. False
a. True
Scroll compressors are more efficient than other types of compressors because _____.