A steam trap that fails to open causes a heating unit to become ___.

The range of pressure on a vacuum switch is usually ___.

Fuel oil burners include atomizing and rotary cup burners.

The range of pressure on a vacuum switch is usually ___.

Air or gases flow from a location of low pressure to a location of high pressure.

Sensible heat is heat that ___.

Air or gases flow from a location of low pressure to a location of high pressure.

___ combustion is combustion that occurs when fuel is burned using only the theoretical amount of air.

The ___ are environmental standards for ambient pollutant emissions from new sources of emissions.

___ combustion is combustion that occurs when fuel is burned using only the theoretical amount of air.