Gas furnace sequence, combustion, heat pump operation, defrost cycle and controls.
39 cards · basic cards · AI-written, checked twice. Edit anything.
- What initiates the furnace startup sequence?
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Thermostat call for heat- Name the four main components of a gas furnace.
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Heat exchanger, burner, blower, and draft inducer- What does the draft inducer accomplish?
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Creates negative pressure to pull flue gases out of the furnace- When does the furnace ignition system fire?
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After the draft inducer proves proper airflow and draft- What is the heat exchanger's purpose?
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Transfers heat from combustion gases to the circulating air- What type of fuel does a typical gas furnace burn?
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Natural gas or propane- Describe the standard furnace startup sequence.
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Call for heat, draft inducer starts, ignition fires, gas valve opens, flame detection confirms- What is the most common type of flame sensor?
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Rod-type sensor or flame rectification sensor- List the three elements required for combustion.
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Fuel, oxygen, and ignition source (heat)- What happens during the combustion process?
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Gas and air mix and ignite, releasing heat energy- What are the main gases produced during furnace combustion?
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Carbon dioxide and water vapor- What does the air intake provide to the furnace?
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Oxygen needed for the combustion process- What safety device stops gas flow when flame is lost?
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Flame sensor or safety switch- What is a rollout switch?
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Safety device that stops gas supply if flames escape the combustion chamber- What happens if the draft switch fails?
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Gas valve will not open and the furnace will not ignite
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