Unit - 14 HVAC

Which refrigerant change in the condenser causes the refrigerant temperature to drop until it reaches the saturation temperature?

• Condensing

• Superheating

• Subcooling

• Desuperheating

Which change to the refrigerant in the condenser results in the largest rejection of heat?

• Superheating

• Desuperheating

• Subcooling

• Condensing

How does the airflow across a forced-draft condenser differ from the flow across an induced-draft condenser?

• Airflow is pushed across the forced-draft condenser and is moved by convection across an induced-draft condenser

• Airflow is pushed across the forced-draft condenser and pulled across an induced-draft condenser

• Airflow is pulled across a forced-draft condenser and pushed across an induced-draft condenser

• Airflow is moved by convection across a forced-draft condenser and is pulled across an induced-draft condenser

Where would you expect a remote air-cooled condenser to be located?

• In the lower part of the cabinet that houses the refrigeration unit

• In a location separate from all of the other refrigeration components

• In a unit with the evaporator that is separate from the compressor

• In a unit with the compressor that is separate from the blower coil

Why is low ambient control needed for buildings with excessive indoor heat loads and air-cooled condensers when outdoor temperatures are low?

• To decrease the indoor heat load of the building to the point of the outdoor temperature

• To increase the temperature of the ambient air surrounding the condenser

• To maintain a minimum head pressure and ensure proper feeding of refrigerant to the evaporator

• To adjust fixed-restriction-type metering devices to account for weather conditions

How are fan-cycling, fan speed, and damper low ambient control methods similar to one another?

• They all reduce or restrict the amount of airflow over the condenser coil

• They all cause a reduction in amp draw by blocking discharge from the fans

• They all reduce the amount of current delivered to the fan motor

• They all use a liquid receiver to back liquid refrigerant up into the condenser tubes

Which tools are most appropriate for removing light surface accumulation of dirt from a condenser?

• Coil cleaning chemicals and personal safety gear

• Stiff bristle brush and vacuum cleaner

• Fin comb

• Water and scrub brush

  Nice work!

When would a fin comb be used to service an air-cooled condenser?

• When the condenser is coated in a light accumulation of dirt

• When more than 20% of the fins have been damaged

• When the condenser is coated in heavy, greasy dirt

• When 20% or less of the fins have been damaged

Which of the following describes the typical construction of a tube-in-tube water-cooled condenser?

• A small tube that carries water is enclosed in a larger tube that carries refrigerant

• Finned copper coil that carries refrigerant is enclosed in a welded steel compartment that contains water

• A small tube that carries refrigerant is enclosed in a larger tube that carries water

• Finned copper coil that carries water is enclosed in a welded steel compartment that contains refrigerant

Why is counterflow used in tube-in-tube condensers?

• Why is counterflow used in tube-in-tube condensers?

• To separate cooling tower water from condenser water

• To prevent cross-contamination between refrigerant and water

• To improve the corrosion resistance of the tubes