Indoor air quality issues can originate in any part of a building.  One of the more obvious origins, and an area most often blamed for IAQ problems, is:

What size should the combustion air ducts be for a mechanical room with an 90,000 BTU/hr furnace and a 35,000 BTU/hr water heater if the air is traveling through horizontal ducts from the outside?

The input Btu rating of a gas furnace is 105,000 Btu. The gas heating value of one cubic foot of natural gas is 1030 btu. Calculate the cubic feet per hour of gas the furnace requires to operate. (Rounded up to whole numbers)

Outdoor combustion air shall be provided through openings not less than 3 inches. Attics and crawl spaces are an acceptable source of combustion air when they are vented by mechanical means.

Arc-resistant-jacketed CSST is considered bonded when it is connected to an appliance that is properly grounded..

The voltmeter will have to be connected to the circuit or load in _________ in order to determine the applied voltage or voltage drop of the loads in the circuit.

A _________________ type flame sensor is a device that will generate a small voltage when heated.

Which electrical failure would correspond to the following Ohmmeter readings?Common, Start, Common and Run terminals to compressor case = 0 Ohms

How does the amount of excess combustion air affect the percentage of carbon dioxide measured in the flue gas?

Liquidtight flexible non-metal conduit shall be securely fastened and supported: