Which of the following statements is correct?
Pressure is defined as:
a) Weight per cubic foot.
b) Force (as measured by weight) exerted against
... [Show More] known area.
c) Force (as measured by weight) exerted against known volume.
d) All of the listed choices - ✔✔ B
Which of the following statements is correct?
a) Gases flow from a low pressure to a higher pressure.
b) Gases do not flow unless pushed by mechanical devices.
c) Gases flow from a high pressure to a lower pressure.
d) Gases flow only under high pressure. - ✔✔ C
Which of the following statements is correct:
a) Draft pressure measurements employ the inches of water column scale
b) Approximately 28 of water column pressure equals 1 lb. per square i of gauge pressure (psig).
c) Pascals are small units of pressure in the metric measurement system
d) of the listed choices. - ✔✔ D
Atmospheric pressure____________( increases decreases ) with increased height above sea level and __________ (varies or stays the same) with changing weather systems and conditions. - ✔✔ Decreases, varies
Which of the following statements is correct?
a) Zero absolute pressure is the same as zero atmospheric pressure.
b) Positive gauge pressure is the same as negative
atmospheric pressure.
c) Vacuum pressure is less than atmospheric pressure.
d) Positive pressure is less than atmospheric pressure. - ✔✔ C
True or False:
A tightly sealed house with few cracks or openings will assist in air delivery to the burner and venting of the products of combustion? - ✔✔ False
Define draft intensity - ✔✔ A current of air
True or False:
To adjust any draft measurement gauge to read zero, one of the two sensing ports on the instrument must be plugged - ✔✔ False
The greater the pressure difference from zero atmospheric pressure the _________________ (greater or lesser) the draft intensity and the ______________ (greater or lesser) the flow rate from _______________ (high to low or low to high) pressure. - ✔✔ Greater, greater, high to low
10. Which of the following statements is correct:
a) An incline manometer is a hand-held measuring instrument.
b) A Draftrite gauge can be held at any angle while taking the draft measurement.
c) A MZF Draft gauge is a larger version of the Draftrite and can also be hand-held while taking the draft measurement.
d) Electronic pressure meters do not have to be level or free of vibration while taking the draft measurement - ✔✔ D
True or False:
An incline manometer is ideal for checking the calibration or accuracy of other draft measuring instruments because it directly indicates pressure - ✔✔ True
Explain why a negative pressure inside the appliance and vent connector does not cause air to flow down the chimney to equalize the lower pressure - ✔✔ The negative measurement is actually a suction pressure created by the higher pressure hot flue gases in the vent that are flowing toward the lower atmospheric pressure.
Which of the following statements is correct:
a) Air supply made available to a burner is always at atmospheric pressure and never higher
b) Draft tests are best conducted when the appliance is not operating
c) Draft tests are best operation conducted when the appliance is at steady-state operation.
d) Draft tests are best conducted when the appliance is just activated. - ✔✔ C
True or False:
Overfire draft is the most important draft measurement to take on an appliance. - ✔✔ True
For most residential oil-fired appliances, the overfire draft reading should be:
a) -.01" wc to -.02" wc
b) +.01" wc to +02" wc
c) -.03" wc to -.06" wc
d) Does not really matter as long as it is negative. - ✔✔ A
Which of the following statements is not correct:
a) Appliances with sealed combustion and venting systems may have a positive draft pressure.
b) Appliances with sealed combustion and venting systems must have a negative draft pressure
c) A breech draft reading is taken at the same sampling location as steady-state efficiency tests.
d) An overfire draft reading is taken in the heat exchanger just over the flame. - ✔✔ B
A higher overfire draft allows _______________ (increased or decreased) excess air entry to the combustion chamber and allows ________________ (proper or excessive) burner air delivery to the combustion chamber. - ✔✔ Increased, excessive
True or False:
A steady-state minimum draft is required by both positive and negative draft venting systems - ✔✔ True
Define draft loss as it relates to a heat exchanger - ✔✔ Difference in measurement of the over-fire and the breech draft readings. Delta T pressure drop.
Draft that is caused by the pressure difference of hot gases rising in a chimney is called by:
a) Induced mechanical draft
b) Natural forced draft
c) Natural thermal draft
d) Uplift draft - ✔✔ C
Wind blowing across a chimney top or vent termination that creates a ____________ (positive or negative) pressure which ____________ (increases of decreases) draft at the appliance; wind blowing down on a chimney creates __________ (positive of negative) pressure which _____________ (increases or decreases) draft at the appliance. - ✔✔ Negative, increases; positive, decrease [Show Less]