The primary control for all HVACR functions in a direct digital control (DDC) system is

A) Not necessary. DDC systems do not use primary controllers
B) A computer
C) A multistage thermostat
D) A relay pack


B

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An SSOLR initiates a trip if the phase currents exceed what percentage of the trip current dial setting?

a. 80% b. 100% c. 125% d. 150%

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What is present in the greatest quantity (by mass) in a diesel engine cylinder at the moment of ignition?

A. fuel B. hydrogen C. nitrogen D. oxygen

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Which of the following letters in the figure above shows a dimension of 0?-3??


a. A
b. B
c. C
d. D

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A room in a house is 14 feet 6 inch by 12 feet 6 inches.  It has 8-ft ceilings.What must the air flow into the room be in cubic feet per minute to have 6 air changes per hour?  Round the answer to the nearer hundredth CFM if needed.

Fill in the blank(s) with the appropriate word(s).

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