HVAC FC 07

What percentage of a refrigeration load can be placed on an evaporator regulated by a two temperature valve?

• 0.2
• 0.3
• 0.4
• 0.5

According to the OSHA safety and health regulation for construction, a fatal accident that results in a death must be reported no later than ___.

• 1 hour
• 4 hours
• 8 hours
• 24 hours

When computing heat leakage for a building, the U-value for most types of construction can be obtained from reference books. The unit of measure for U-value is expressed in ___.

• Btu/sq-ft/deg.F/Hr
• CFM/Hr
• heat-flow / square-area
• heat-flow / temperature-difference / area

Carbon dioxide stack changes with respect to the amount of excess air (oxygen) in the area. Systems will vary in the CO2 content operating between 8% to 12%. If a system uses a oil-fired heating system, what would be the CO2 content of flue gas, given that the excess air in the system was approximately 80%?

• 0.12
• 0.1
• 0.09
• 0.07

Volatile liquid is located in the ___ and this is in contact with the evaporator of the refrigeration system.

• Bi-metal
• Solid state
• Cap tube
• Sensing bulb

Slowing the velocity of water through an evaporator will have what effect on the heat transfer?

• increase
• decrease
• no change
• slightly improve

How many CFM of ventilation air is required for a 50,000 Btu/hr infrared heater?

• 100
• 200
• 300
• 400

Energy conservation standards require that each walk-in cooler or walk-in freezer manufactured on or after January 1, 2009, shall contain wall, ceiling and door insulation of at least R-25 for coolers and ____ for freezers.

• R-25
• R-28
• R-32
• R-40

Troubleshoot the following conditions: The ohmmeter when across the start capacitor goes to low range, then slowly moves to the high range of the scale.

• indicates a short
• indicates an open
• good start capacitor
• bad motor winding

Which method of heat transfer is characterized by heat traveling through a substance by direct contact?

• radiation
• conduction
• convection
• combustion