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56

Competency and Task List

Gas Heat

Students must

have

knowledge of

heating sys-

tems, their

components,

and be able to

demonstrate

proficiency in:

Describing and explaining the function of upflow, downflow, and horizontal furnaces

Explaining combustion Theory and Heating Fuels

Explaining the Properties of Heaitng Fuels

Define BTU

Define AFUE

Describing and using the formula for sensible heat

Describing the principles of humidification

Describing the principles of dehumidification

Explaining the BTU content of natural gas and propane gas

Describing the fuel pressures in natural gas and liquefied petroleum (LP) gas piping

Describing and measuring operating fuel pressures in natural gas and liquefied petroleum (LP)

furnaces

Describing the typical flue gas temperatures of gas-fired furnaces

Describing the chemical names of natural gas and propane gas

Determining the quantity of combustion air required to burn 1 cubic foot of natural gas and

propane gas

Defining and differentiating between primary air and excess air

Stating the maximum percentage of Carbon Dioxide produced by the perfect combustion of

natural gas

Stating the maximum percentage of Carbon Dioxide produced by the perfect combustion of

propane gas

Explaining the ignition temperatures of natural gas and propane gas

Describing and stating the causes of burner “Flashback”

Describing and stating the causes of a lifting flame.

Stating the reason for appropriate polarity wiring on solid state circuits

Stating the generally accepted standard gas manifold pressure for a residential furnace

Describing, explaining the function, evaluating, cleaning, and replacing (when feasible) of the

following components:

Gas valves used with residential furnaces

Gas pressure regulating valves

Orifice

In-shot burner

Pilot burner

Heat exchanger

Flue baffles

Residential gas shutoff valve

Thermocouple

Thermopile

Ignition module

Spark igniter

Hot surface igniter

Flame sensor

Combination fan and limit switch

Door safety switch

Blower motor relay

Vent blower motor

Vent pressure switch

Vent motor relay