Which of the following statements about coil surfaces is false?

Which of the following statements about coil surfaces is false?

a) Air flows across the fins
b) Finned coils are more compact than smooth tube coils of the same capacity
c) Fins increase the contact surface area between the airstream and the tubes
d) All fins must be crimped
e) Finned coils are less expensive than smooth coils of the same capacity








Answer: D

Which one of the following methods is not a method of ensuring uniform steam distribution in steam coils?

Which one of the following methods is not a method of ensuring uniform steam distribution in steam coils?

a) installation of distributing plates within the steam header
b) "steam distributing" coils
c) installation of individual orifices into the supply end of each tube
d) once called "non-freeze coils"
e) controlling the face velocity of the air flowing over coils







Answer: E

Half serpentine water coil circuiting is used

Half serpentine water coil circuiting is used

a) in applications requiring high water velocities and low water pressure drops
b) where the water velocity in the tubes is more than 2.4 m/s
c) where the water velocity in the tubes is between 0.3 and 2.4 m/s
d) for any water velocity in the tubes
e) where the water velocity in the tubes is less than 0.3 m/s






Answer: E

Double serpentine water coil circuiting is used

Double serpentine water coil circuiting is used

a) where the water velocity in the tubes is less than 0.3 m/s
b) where the water velocity in the tubes is more than 2.4 m/s
c) for any water velocity in the tubes
d) where the water velocity in the tubes is between 0.3 and 2.4 m/s
e) in applications requiring low water velocities and low water pressure drops







Answer: B

Single serpentine water coil circuiting is used

Single serpentine water coil circuiting is used

a) where the water velocity in the tubes is less than 0.3 m/s
b) where the water velocity in the tubes is more than 2.4 m/s
c) for any water velocity in the tubes
d) where the water velocity in the tubes is between 0.3 and 2.4 m/s
e) in applications requiring high water velocities and low water pressure drops







Answer: D

Which of the following statements about water coils is false?

Which of the following statements about water coils is false?

a) Coils should be hooked up in a counterflow arrangement.
b) Coils need to be able to vent air.
c) Adequate air velocity over the finned surface must be maintained.
d) Circuiting should minimize the performance of the water flow versus the pressure drop through the coil.
e) The bottom connection should always be the water inlet.

Answer: D

Steam Coils must be designed to: i) constantly eliminate air ii) constantly eliminate condensate iii) constantly eliminate noncondensable gases iv) constantly maintain face velocity v) constantly eliminate air venting

Steam Coils must be designed to:
i) constantly eliminate air
ii) constantly eliminate condensate
iii) constantly eliminate noncondensable gases
iv) constantly maintain face velocity
v) constantly eliminate air venting

a) ii, iii, and v
b) iii only
c) ii and iv
d) i, iii, iv, and v
e) i, ii, and iii








Answer: E

Air venting is required for which of the following reasons?

Air venting is required for which of the following reasons?

a) To assure adequate water distribution in supply and return lines
b) To assure adequate air distribution in supply lines
c) To assure adequate air distribution in return lines
d) To maintain face velocity
e) All of the above







Answer: A

The face velocity of a heating or cooling coil is the:

The face velocity of a heating or cooling coil is the:

a. Velocity of the supply water to the coil
b. Velocity of the air before it enters the coil
c. Velocity of the air after it leaves the coil
d. Average velocity of the air flowing over the face area of the fin surface
e. Velocity of the steam entering the coil








Answer: D

Which of the following is a limiting factor for the fin spacing of an HVAC coil

Which of the following is a limiting factor for the fin spacing of an HVAC coil

a. Temperature of steam in coils
b. Temperature of chilled water in the coils
c. Fin material
d. Resistance to airflow
e. Face velocity







Answer: D

To obtain full rated capacity of hot water heating coils,

To obtain full rated capacity of hot water heating coils,

a. Connect the water supply for counter flow
b. Connect the water supply for parallel flow
c. Choose a coil with fewer fins per unit length of coil
d. Connect the coils with a staggered tube design
e. Increase the face velocity








Answer: A

Finned tube coils in air handling systems are often called:

Finned tube coils in air handling systems are often called:

a. Fish coils
b. Bare tube soils
c. Extended surface coils
d. Cooling coils
e. Heating coils






Answer: C

Which of the following statements about steam distributing heating coils is true?

Which of the following statements about steam distributing heating coils is true?

a. The coils are freeze-proof
b. The coils distribute steam evenly over the entire coil
c. The coils are used when steam cannot be throttled
d. The coils cannot be used where freezing air temperatures are frequently encountered over the coil
e. The coils can only have same end connections






Answer: B

The most vital element to ensure effective heat transfer in a fin-type heat exchanger coil used for HVAC service,

The most vital element to ensure effective heat transfer in a fin-type heat exchanger coil used for HVAC service,

a. The fin must be crimped
b. The fins must be made of highly conductive material
c. A good bond must exist between the tube and fin
d. Narrow fin spacing is necessary
e. Wide fin spacing is necessary






Answer: C

To assure air is properly vented from a heating or cooling coil,

To assure air is properly vented from a heating or cooling coil,

a. Return water connection should be at the bottom of the coil
b. Supply water connection should be at the bottom of the coil
c. Supply water connection should be at the top of the coil
d. Vent should be located at the lowest points of the supply and return lines, and of the coils
e. Double serpentine water coil circuit should be used






Answer: B

Two types of modern coils used for heating and cooling services in air handling systems are:

Two types of modern coils used for heating and cooling services in air handling systems are:

a. The continuous-plate finned surface and the spiral-finned surface
b. The bare tube and the spiral-finned surface
c. The continuous-plate finned surface and the bare tube
d. The bare tube and the in-line fin-tube
e. The staggered bare tube and the fin-tube





Answer: A

Which type of heating coil circuiting is designed to produce a high heat capacity with limited water supply?

Which type of heating coil circuiting is designed to produce a high heat capacity with limited water supply?

a. Single serpentine
b. Double serpentine
c. Half serpentine
d. Face velocity
e. Steam coil






Answer: C

In order to provide uniform steam distribution to the individual tubes of a steam coil, steam coils are designed to

In order to provide uniform steam distribution to the individual tubes of a steam coil, steam coils are designed to

a. Constantly eliminate air
b. Constantly eliminate condensate, air, and non-condensable gases
c. Constantly eliminate non-condensable gases
d. Be installed with counterflow
e. Provide minimal pressure drop across the coil






Answer: B

Flat-finned surface type coils are normally used for:

Flat-finned surface type coils are normally used for:

a. Steam heating purposes
b. Water heating purposes
c. High temperature application
d. Low temperature application where ice may form
e. Greater turbulence of air at the fin surface







Answer: D

With counter flow arrangement of air and water in a cooling or heating coil:

With counter flow arrangement of air and water in a cooling or heating coil:

a. The water supply connection is on the same side as the entering air
b. The heat transfer efficiency is the same as with parallel arrangement of air and water
c. The water supply connection is on the same side as the air leaving the coil
d. The water return connection is on the same side as the leaving air
e. It decreases the heat transfer efficiency






Answer: C