HVAC State Test Prep 03

The optimum air-fuel ratio for natural gas in gas burners under standard conditions is approximately

• 1.5
• 4.5
• 9.5
• 10.5

The most common fuel gas used in comfort heating is:

• butane
• propane
• natural
• coke oven

Fuel oil used for oil burners is a no. 6 that is black and _________.

• thin
• thick
• both of these
• neither of these

No. 1 fuel oil for oil burners is very _________ and colorless and resembles kerosene.

• opaque
• jelly-like
• thick
• thin

Atomization is the process whereby oil is _________ into fine droplets.

• mixed
• broken
• vaporized
• heated

The basic devices used for fuel control are:

• pumps
• relief valves
• metering valves
• pressure reducing valves
• all of the above none of the above

Small boiler systems—those having capacities of 10,000 pounds per hour of steam or less—are often equipped with underfeed stokers in which the fuel is forced into the combustion area by a ram or

• screw
• stoker
• rake
• hopper

Spreader stoker systems are often used in boilers designed to generate steam in quantities of

• 25000
• 50000
• 75000
• 100000

Fuel-air ratio control equipment can be classified in three general groups: atmospheric, fixed-flow, and

• variable
• low
• high
• none of these

Two of the most commonly measured combustion products are oxygen and _________.

• carbon dioxide
• carbon monoxide
• soot
• ashes