One gallon of #2 fuel oil contains about ______ Btu of potential heat energy:

The angle selected for oil spray will depend on which of the following:

OSHA standards prohibit worker exposure to Carbon monoxide not more than _____ PPM air averaged during an 8 hour period:

Joint compound in gas piping is applied sparingly to the ______ threads only

The optimum excess air required for the complete combustion of natural gas fuel burners will be approximately:

Which of the following gas is the main constituent in Natural gas:

Nozzles are rated in ________:

In ________ the cooler air is drawn at the base of the furnace, and the warm air exits out the top of the furnace:

When there is an increase in the primary air, which of the following is not correct:

Efficiency of the boiler is inversely proportional to the number of passes:

In the air stream leaving direct gas-fired units, concentrations of Carbon monoxide as per ANSI shall not be more than _______

Heat pumps with the highest SEERs and HSPFs invariably use variable or two-speed ______ compressors:

Convective heating should be used in draughty rooms, rooms with high ceilings or areas with open stairwells:

Hydronic heating systems use ______ to move heat from where it is produced to where it is needed:

These older natural gas systems usually have seasonal efficiencies of about ______ :