Advanced Propane Appliances and Electrical Circuits

A comprehensive set of vocabulary flashcards covering basic and advanced propane appliance components, electrical circuit principles, troubleshooting, and airflow management based on the lecture notes.

Basic Appliances

Appliances that include standing pilot ignition systems, ranges with electric spark ignition, and ovens with hot surface ignition systems; some use millivolt systems drawing current from a thermocouple or thermopile.

Advanced Appliances

More complex propane appliances featuring advanced controls, electronic ignition systems, and circuit boards that connect most components to control electricity flow.

Integrated Furnace Control (IFC) board

A circuit board that serves as the control center of the electrical system, monitoring and controlling all furnace operations.

Flame Rectification

The principle used by electronic ignition systems to verify flame presence by converting alternating current ($AC$) to direct current ($DC$) through the flame.

Induced Draft Blower

A component that pulls combustion gases through the heat exchanger, sometimes adjusting motor speed automatically to ensure complete combustion and peak efficiency.

Air Handling System

A system including the blower motor, blower wheel, and filters that moves heated air from the heat exchanger throughout the duct system.

Arc Flash

A sudden high-voltage arc of electricity that is extremely dangerous and can be caused by tools creating a short in an energized circuit.

Main Circuit Breaker

A breaker in the electrical panel used to power all the circuits in a building on or off at one time, fed by two thick black wires from the power company.

Neutral Bar

A component connected to the Main circuit neutral wire that returns current back to the source of electricity, such as the power company transformer.

Frequency

The number of cycles completed within one second, measured in hertz ($Hz$); in North America, alternating current is at $60\,Hz$.

Single-Phase Current

A single current alternating within a circuit, commonly used in most residential power and small $120\,V$ appliances.

Three-Phase Current

A system where three currents alternate at different time intervals ($120$ degrees out of phase) within the same circuit, often used for larger motors in commercial applications.

Spill Switch

A normally closed ($NC$) safety switch wired in series with the gas valve that opens to cut power if it detects harmful products of combustion or abnormal high temperatures.

Water Flow Switch

A device used in hydronic boilers or on-demand heaters to prevent the burner from operating if the flow rate of water is inadequate.

Fixed Resistor

An electrical component that provides a specific, unchanging amount of resistance to limit the current passing through a circuit.

Thermistor

A variable resistor that changes its resistance when temperature changes; it is the most used temperature sensor in HVAC applications.

Black Boxes

The largest components on a circuit board, which serve as processors, relays, and sometimes transformers.

Dip Switch

Small switches on a circuit board used to specify settings, such as fan on and off delays, upon appliance installation or during service.

Differential Temperature (Delta T)

A value calculated by subtracting one temperature from another to verify if an appliance's temperature rise matches manufacturer specifications.

Gauge Pressure

A pressure measurement comparing pressure at one point to ambient atmospheric pressure, commonly measured in $psig$ or inches of water column ($w.c.$).

PSC Motor

Permanent Split-Capacitor motor, commonly used in propane furnaces to operate the main blower, involving a capacitor connected in series with the motor start winding.

ECM Motor

Electronically-Commutated Motor which includes a microprocessor to control performance, such as varying motor speed to maintain constant airflow.

Contactor

A large relay used when more than $20\,amperes$ are needed to complete a circuit to a load, such as a motor.

Electronic Fan Timer

A control that improves system efficiency by managing the delay between furnace ignition and fan start, or between furnace shutdown and fan stop.

Air-Proving Switch

A normally open ($NO$) pressure or vacuum actuated switch connected to the draft inducer that closes when sufficient draft is established to energize the ignition system.

Post-Purge Cycle

A period where the draft inducer continues to run for a few seconds after the burners go out to clear remaining flue gases.

Humidistat

A control device in a room or ductwork that measures the amount of moisture in the air and activates the humidifier.

Electronic Air Cleaner (EAC)

A device that removes small particles from air by charging them with high positive voltage so they adhere to negatively charged grids.

Power Venter

A motorized blower used to vent products of combustion to the outside, typically utilized in the absence of a chimney or gas vent.

Inshot Burners

A burner type where an air/gas mixture passes through a burner head insert and forms a flame that projects downstream into the heat exchanger.

Pre-Mixing Burners

Burner systems where all combustion air is mixed with fuel gas at an optimum ratio prior to ignition, resulting in a compact blue flame.

Flame Rod Sensor

A component of electronic ignition systems that protrudes into the flame and uses flame rectification to sense flame intensity.

Microamp ($\mu A$)

A unit of measurement equal to one millionth of an amp ($0.000001\,amp$) used to measure the flame signal in electronic ignition systems.

Signal Transducer

A device attached to a multimeter that measures microamps and converts the values to $DC$ volts for easier reading ($1\,V\,DC = 1\,\mu A$).

Intermittent Spark Ignition (ISI)

An ignition system that uses a spark electrode to ignite a pilot flame only when the thermostat calls for heat, rather than using a continuous pilot.

Direct Spark Ignition (DSI)

An ignition system that lacks a pilot burner and instead uses a spark igniter to light the main burner directly upon a call for heat.

Ductwork Plenum

A metal fabricated box connected to the furnace that distributes supply air or collects return air.

Static Pressure

The pressure applied in all directions to the inside of the duct system, measured in units like $in.\,w.c.$; the recommended residential setting is typically $0.10\,in.\,w.c.$.

Velocity Pressure

Directional pressure created by the blower wheel that moves warm air through supply ducts and out through registers.