Which of the following gas is lighter than air:

An efficient oil burner is one that burns the fuel oil completely using the ______ amount of air necessary for combustion.

Soldered or sweated connections are also not recommended in ________:

Flame test can be carried out inorder to identify the leaks in the gas piping:

For radiant floor heat, hot water temperature can be much higher than for space heating:

Smoky combustion indicates poor burner performance

The common spark gap between two electrode tips will be about:

For the most efficient operating characteristics, the overfire draft generally should be not less than _______:

In two stage oil pump the _______ stage draws completely air-free oil:

Excessive draft can _______ the percentage of carbon dioxide in the flue gases

_______ fuel spray angles are recommended for long, narrow chambers

______ gives a twisting motion to the air stream just before it strikes the oil spray

No.2 fuel oil has a heating value of about ______ btu per gallon:

Air enters the heating system in following order:

The fuel oil first enters the unit by passing through the _______, where foreign particles such as dirt and line filter fibers are removed.