Question 121
One of the methods used to provide uniform steam distribution to the
individual tubes of a steam coil is: D
A) use longer tubes.
B) employ an orifice at the outlet of each tube.
C) use perforated tubes.
D) use distributing plates within the steam header.
E) use vacuum breakers.
Question 122
Short steam coils are not likely to freeze, providing: B
A) there is a steam trap installed.
B) positive drainage of condensate is ensured.
C) the coils are always under vacuum.
D) the tube length is 2.1 m or less.
E) there is 100% outside makeup air.
Question 123
The most effective method to prevent steam coils from freezing is to
select: E
A) steam coils made of copper.
B) shorter tubes.
C) a modulating steam flow control valve.
D) an oversized steam flow control valve.
E) a two-position control valve.
Question 124
Steam coils with long tubes are more likely to freeze when outside air
temperature is : C
A) extremely low, such as -35?C.
B) moderately low, such as -12?C.
C) mild, such as - 2?C. to -1?C.
D) at any temperature below freezing.
E) at a temperature slightly above freezing, such as 4C.
Question 125
The hazard of freeze-up of a steam coil handling a large amount of outdoor
air is minimized by employing: C
A) a steam coil with longer tubes.
B) a vacuum breaker.
C) a preheat coil.
D) an oversized coil.
E) higher temperature steam.
Question 126
When a preheat coil is employed in an air conditioning system, to prevent
overheating the space temperature the mixing air temperature is limited to: D
A) 12.5°C.
B) 14.5°C.
C) 15°C.
D) 18°C.
E) 20°C.
Question 127
To prevent steam coil freeze up, it is recommended that at the full load of
the coil, the pressure of the steam entering should not be less than about: A
A) 68 kPa
B) 52 kPa
C) 41 kPa
D) 35 kPa
E) 10 kPa
Question 128
At full load conditions, the minimum recommended steam pressure at the inlet
of a steam regulating control valve for a steam heating coil is: C
A) 17 kPa
B) 25 kPa
C) 34 kPa
D) 55 kPa
E) 68 kPa
Question 129
The vacuum breaker on the steam coil is installed: A
A) near the inlet of the steam coil, after the steam control valve.
B) near the outlet of the steam coil, ahead of the steam trap.
C) near the outlet of the steam coil, after the steam trap.
D) near the inlet of the steam coil, ahead of the steam control valve.
E) near the inlet of the steam valve and ahead of the steam trap.
Question 130
Which of the following statements about vacuum breakers is FALSE : E
A) They are used to prevent freeze-ups caused by negative pressure in the
coil.
B) Pipe connections of check valves used as vacuum breakers may be left open
to the atmosphere.
C) Pipe connections of check valves used as vacuum breakers may be connected
to the return header.
D) Vacuum breakers are essential for satisfactory functioning of the steam
trap.
E) The vacuum breaker must be installed before the control valve and as near
as possible to the outlet connection of the coil.
Question 131
When using water coils to heat air at sub freezing temperature, it is
important that: C
A) the hot water flow control valve is able to regulate the flow rate.
B) a counter flow air and water arrangement must be maintained.
C) a constant flow of water is fed to the coil at all times.
D) the outside air damper is closed at all times.
E) the hot water flow rate does not exceed 0.p m/s.
Question 132
To prevent the freeze up of a hot water coil used in sub freezing
temperatures, the velocity of air passing over the coil should not exceed: C
A) 15 m/s
B) 7.55 m/s
C) 3.55 m/s
D) 1.55 m/s
E) 0.75 m/s
Question 133
The greatest fears in hot water coil installations handling sub freezing air
are: D
1. excessive pipe expansion and contraction.
2. outside air temperature too low.
3. failure of the circulation pump.
4. water viscosity too high.
5. failure of the heat source.
A) 1, 2, and 3 ONLY
B) 1, 2, and 4 ONLY
C) 1, 3, and 5 ONLY
D) 3 and 5 ONLY
E) 2, and 3 ONLY
Question 134
A flow switch installed on the hot water heating coil of an air conditioning
system is to: D
A) measure the amount of hot water flow.
B) regulate the flow rate.
C) indicate the pump's pumping efficiency.
D) interlock with the fans and outside air dampers for freeze protection.
E) interlock with the pump to prevent air locking.
Question 135
The use of ethylene glycol solution in a heating coil will result in: B
A)better rate of heat transfer.
B) better protection against freezing.
C) reduced frictional losses in the coil and piping.
D) the requirement of a smaller pump with less horsepower.
E) an overall higher system efficiency.
Question 136
The effects of using ethylene glycol in a hot water heating coil include: D
1. a lower heat transfer rate.
2. better protection against freezing.
3. increased friction losses in the coil and piping.
4. a requirement for a larger pump with more horsepower.
A) 1 and 4 ONLY
B) 1 and 3 ONLY
C) 2, 3, and 4 ONLY
D) 1, 2, 3 and 4
Question 137
On a steam glycol converter, overheating of the glycol may be prevented by
interlocking the steam valve with: A
A) a flow switch in the glycol piping.
B) the relief valve on the glycol piping.
C) a pressure switch on the converter shell.
D) an outdoor air temperature switch.
E) a temperature switch on the glycol inlet piping.
Question 138
To prevent freeze-up of an air conditioning system steam coil, the tubes
should be arranged: C
A) horizontally
B) at a 45?angle.
C) vertically
D) in any manner preferred by the designer.
Question 139
The preferred steam trap for installation on air conditioning heating coils
operating at lower pressures (below 172 kPa) is the _______ type: A
A) float and thermostatic
B) thermodynamic
C) impulse
D) inverted bucket
E) thermostatic
Question 140
The preferred steam trap for installation on air conditioning heating coils
operating at higher pressures (in excess 172 kPa) is the _______ type: D
A) float and thermostatic
B) thermodynamic
C) impulse
D) inverted bucket
E) thermostatic
One of the methods used to provide uniform steam distribution to the
individual tubes of a steam coil is: D
A) use longer tubes.
B) employ an orifice at the outlet of each tube.
C) use perforated tubes.
D) use distributing plates within the steam header.
E) use vacuum breakers.
Question 122
Short steam coils are not likely to freeze, providing: B
A) there is a steam trap installed.
B) positive drainage of condensate is ensured.
C) the coils are always under vacuum.
D) the tube length is 2.1 m or less.
E) there is 100% outside makeup air.
Question 123
The most effective method to prevent steam coils from freezing is to
select: E
A) steam coils made of copper.
B) shorter tubes.
C) a modulating steam flow control valve.
D) an oversized steam flow control valve.
E) a two-position control valve.
Question 124
Steam coils with long tubes are more likely to freeze when outside air
temperature is : C
A) extremely low, such as -35?C.
B) moderately low, such as -12?C.
C) mild, such as - 2?C. to -1?C.
D) at any temperature below freezing.
E) at a temperature slightly above freezing, such as 4C.
Question 125
The hazard of freeze-up of a steam coil handling a large amount of outdoor
air is minimized by employing: C
A) a steam coil with longer tubes.
B) a vacuum breaker.
C) a preheat coil.
D) an oversized coil.
E) higher temperature steam.
Question 126
When a preheat coil is employed in an air conditioning system, to prevent
overheating the space temperature the mixing air temperature is limited to: D
A) 12.5°C.
B) 14.5°C.
C) 15°C.
D) 18°C.
E) 20°C.
Question 127
To prevent steam coil freeze up, it is recommended that at the full load of
the coil, the pressure of the steam entering should not be less than about: A
A) 68 kPa
B) 52 kPa
C) 41 kPa
D) 35 kPa
E) 10 kPa
Question 128
At full load conditions, the minimum recommended steam pressure at the inlet
of a steam regulating control valve for a steam heating coil is: C
A) 17 kPa
B) 25 kPa
C) 34 kPa
D) 55 kPa
E) 68 kPa
Question 129
The vacuum breaker on the steam coil is installed: A
A) near the inlet of the steam coil, after the steam control valve.
B) near the outlet of the steam coil, ahead of the steam trap.
C) near the outlet of the steam coil, after the steam trap.
D) near the inlet of the steam coil, ahead of the steam control valve.
E) near the inlet of the steam valve and ahead of the steam trap.
Question 130
Which of the following statements about vacuum breakers is FALSE : E
A) They are used to prevent freeze-ups caused by negative pressure in the
coil.
B) Pipe connections of check valves used as vacuum breakers may be left open
to the atmosphere.
C) Pipe connections of check valves used as vacuum breakers may be connected
to the return header.
D) Vacuum breakers are essential for satisfactory functioning of the steam
trap.
E) The vacuum breaker must be installed before the control valve and as near
as possible to the outlet connection of the coil.
Question 131
When using water coils to heat air at sub freezing temperature, it is
important that: C
A) the hot water flow control valve is able to regulate the flow rate.
B) a counter flow air and water arrangement must be maintained.
C) a constant flow of water is fed to the coil at all times.
D) the outside air damper is closed at all times.
E) the hot water flow rate does not exceed 0.p m/s.
Question 132
To prevent the freeze up of a hot water coil used in sub freezing
temperatures, the velocity of air passing over the coil should not exceed: C
A) 15 m/s
B) 7.55 m/s
C) 3.55 m/s
D) 1.55 m/s
E) 0.75 m/s
Question 133
The greatest fears in hot water coil installations handling sub freezing air
are: D
1. excessive pipe expansion and contraction.
2. outside air temperature too low.
3. failure of the circulation pump.
4. water viscosity too high.
5. failure of the heat source.
A) 1, 2, and 3 ONLY
B) 1, 2, and 4 ONLY
C) 1, 3, and 5 ONLY
D) 3 and 5 ONLY
E) 2, and 3 ONLY
Question 134
A flow switch installed on the hot water heating coil of an air conditioning
system is to: D
A) measure the amount of hot water flow.
B) regulate the flow rate.
C) indicate the pump's pumping efficiency.
D) interlock with the fans and outside air dampers for freeze protection.
E) interlock with the pump to prevent air locking.
Question 135
The use of ethylene glycol solution in a heating coil will result in: B
A)better rate of heat transfer.
B) better protection against freezing.
C) reduced frictional losses in the coil and piping.
D) the requirement of a smaller pump with less horsepower.
E) an overall higher system efficiency.
Question 136
The effects of using ethylene glycol in a hot water heating coil include: D
1. a lower heat transfer rate.
2. better protection against freezing.
3. increased friction losses in the coil and piping.
4. a requirement for a larger pump with more horsepower.
A) 1 and 4 ONLY
B) 1 and 3 ONLY
C) 2, 3, and 4 ONLY
D) 1, 2, 3 and 4
Question 137
On a steam glycol converter, overheating of the glycol may be prevented by
interlocking the steam valve with: A
A) a flow switch in the glycol piping.
B) the relief valve on the glycol piping.
C) a pressure switch on the converter shell.
D) an outdoor air temperature switch.
E) a temperature switch on the glycol inlet piping.
Question 138
To prevent freeze-up of an air conditioning system steam coil, the tubes
should be arranged: C
A) horizontally
B) at a 45?angle.
C) vertically
D) in any manner preferred by the designer.
Question 139
The preferred steam trap for installation on air conditioning heating coils
operating at lower pressures (below 172 kPa) is the _______ type: A
A) float and thermostatic
B) thermodynamic
C) impulse
D) inverted bucket
E) thermostatic
Question 140
The preferred steam trap for installation on air conditioning heating coils
operating at higher pressures (in excess 172 kPa) is the _______ type: D
A) float and thermostatic
B) thermodynamic
C) impulse
D) inverted bucket
E) thermostatic
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