Which of the following are both used to service a fuel unit:

Which of the fuel pumps are used with underground fuel tank applications:

Fuel Pump fail to prime when Suction inlet vacuum is greater than _______ of vacuum

Too much _____ causes the flame to lift off the burner ports:

Which of the fuel oil gives more heat per gallon used.

The efficiency or coefficient of performance (COP) of ground-source heat pumps is significantly ______ than that of air-source heat pumps:

When there is a decrease in the primary air, which of the following is correct:

Gross stack temperature will be in the range of ______:

Delayed ignition is mainly traced to a problem with which of the following:

A draft hood will also control backdrafts that tend to extinguish the gas burner flame and the amount of excess air.

In ____ boilers, hot combustion gases pass through tubes submerged in water:

_______ is caused by the accumulation of fuel oil in the combustion chamber of the furnace or boiler after an ignition failure.

Which of the following heating systems normally offer the most cost effective way to heat large buildings:

Which of the following oil burner has relatively high operating cost

Natural gas has a heating value of approximately _______ Btu per cubic foot: