Combustion Theory and Heating Fuels

• State the BTU content of various fuels.
• State the specific gravity of various fuels.
• Describe the various categories of furnaces as classified by the National Fuel Gas Code.
• State the typical flue gas temperatures of the varying categories of furnaces.
• State the proper chemical names of various fuels.
• Define BTU
• Determine the quantity of combustion air required to burn one cubic foot of various fuels.
• State the ignition temperature of various fuels.
• Define and differentiate between primary air and excess air.
• State the cubic feet of flue gas required for every one cu ft. of various fuels burned.
• Describe and state the causes of burner “Flashback”.
• Describe and state the causes of a lifting flame.
• Describe and state the causes of yellow flame.
• Describe and state the causes of floating flame.
• State the percentage of Carbon Dioxide present in the flue gases of a natural gas furnace, if perfect combustion occurred.
• State the percentage of Carbon Dioxide present in the flue gases of a properly operating LP furnace.

Safety

• State the national standard for burners and ignition source height for a garage installation.
• Describe and demonstrate ladder safety procedures.
• Describe the safety procedure to be followed upon discovery of a defective heat exchanger.
• State the distance that type B vent pipe must be kept from combustible materials.
• State the minimum number of inches required for service access.
• Determine the acceptable ppm of Carbon Monoxide in a flue gas sample.
• State the proper safety procedures to follow upon discovering a gas leak.

Knowledge of Heating Systems and Components

• Describe the operation of and test a thermocouple.
• Describe the operation of and test a millivolt generator.
• Describe the operation of and test a door safety switch.
• Describe the operation of and test a spark igniter.
• Describe the operation of and test a hot surface igniter.
• Describe the operation of and test a flame sensor.
• Describe the operation of and test an ignition module.
• Describe and test the operation of gas valve used with residential furnaces.
• Describe the operation of and test a vent pressure switch.
• Describe a pilot burner and orifice and explain its operation.
• Describe a main burner and orifice and explain its operation.
• Describe the operation of and test a combustion fan limit switch.
• Describe the various fan controls and test their operation.
• Describe the operation of and test a limit switch.
• Describe the operation of and test a blower motor relay.
• Describe the operation of and test a vent motor relay.

Knowledge of Heating Systems and Components (Continued)

• Describe the operation of and test a vent blower.
• Describe and inspect the condition of a heat exchanger.
• Describe, test, and install a run and start capacitor.
• Describe and set a heat anticipator on a thermostat.
• Describe and install a single stage thermostat.
• Describe and install a dual stage thermostat.
• Adjust primary air and describe the procedure.
• Describe and clean flue baffles.
• Describe and install a blower housing cut-off plate.
• State the materials used in the construction of Type B vent pipe.
• Measure static pressure and describe the appropriate range in residential furnaces.
• Describe the types of burners used on residential gas furnaces.
• Differentiate between the bonnet rating and input rating of a furnace.
• State the reason for appropriate polarity wiring on solid state circuits.
• Describe the principles of dehumidification and humidification.

Installation and Service

• State the generally accepted standard gas manifold pressure for a residential furnace.
• Measure manifold gas pressure.
• Describe the proper venting configurations of mid and high efficiency furnaces.
• State the National Fuel Gas Code maximum fuel line pressure drop allowance.
• State the proper procedures for installation of gas piping.
• Cut and thread gas pipe.
• State the standard acceptable supply pressures of various fuels.
• Describe the purpose of and install a fire stop support plate.
• Describe the types of and install duct connectors and hangers.
• Describe “R” values and noise reduction elements of various duct materials.
• Describe and size wire as it applies to voltage drop and length of wiring run.
• Describe and demonstrate proper soldering procedures for electrical wiring.
• Describe the procedure and adjust air flow on a belt driven blower assembly.
• State the formula for sensible heat.
• Describe the procedure to de-rate a gas furnace at altitudes of 2,000 feet and above.
• Identify the different types of conduit used for power wiring.
• Adjust blower fan speed.

Gas Heat Troubleshooting and Problem Solving

Troubleshooting and Problem Solving involves diagnostic procedures requiring the use of test instruments, data plate information, and wiring diagrams. All of the gas furnace system components, circuits, air distribution system, and/or power supply should be part of Troubleshooting and Problem Solving.

Knowledge of the following test instruments and or tools is required.

• Combustion analyzer Tap and die set
• Combustible gas detector Pipe cutter
• Carbon Monoxide detector Pipe Reamers
• Manometer Velometer
• Voltmeter Ammeter
• Soldering and brazing equipment Ohmmeter