FURNACE BASICS
THIS COMPONENT PROVES THAT THE FLAME IS PRESENT AND SAFE TO KEEP GAS FLOWING
WHAT IS A FLAME SENSOR?
THIS DEVICE GLOWS HOT TO INGNITE THE GAS IN MANY MODERN FURNACES.
WHAT IS THE HOT SURFACE IGNITER?
what powers the low voltage
transformer
MOST FURNACES USE THESE FLASHING LIGHTS TO DISPLAY ERROR CODES.
WHAT ARE LED ERROR CODE LIGHT'S?
THE FIRST STEP BEFORE TROUBLESHOOTING A FURNACE.
WHAT IS CHECK POWER SUPPLY AND THERMOSTAT CALL?
what is in-between the low voltage terminal and transformer
low voltage fuse
IF THIS SAFTEY SWITCH OPENS DUE TO OVERHEATING, THE BURNER WILL SHUT DOWN.
WHAT IS THE HIGH LIMIT SWITCH?
what prevents power to a unit for safety reasons
WHAT IS THE DOOR SWITCH?
WHAT TOOL IS USED TO INSURE PROPER COMBUSTION OF GAS IN A FLU PIPE
WHAT IS A COMBUSTION ANALYZER?
A MANOMETER IS USED TO MEASURE THIS IN A FURNACE
WHAT IS GAS PRESURE?
THIS DEVICE MONITORS VENT PRESURE TO ENSURE SAFE COMBUSTION AIRFLOW,
WHAT IS THE PRESURE SWITCH?
THIS HAPPENS IF THE FURNACE CONTROL BOARD DOES NOT SENSE A FLAME WITHIN A FEW SECONDS OF IGNITION
WHAT IS A LOCKOUT OR IGNITION FAILURE?
HIGH TEMPERATURE LIMIT SWITCHES OFTEN TRIP BECAUSE OF THIS AIRFLOW-RELATED PROBLEM.
WHAT IS RESTRICTED AIRFLOW OR BLOCKED FILTER/DUCT?
A PRESURE SWITCH STUCK CLOSED BEFORE THE INDUCER STARTS CAUSES THIS FAULT?
WHAT IS AN INDUCER OR PRESURE SWITCH ERROR?
YOU WOULD USE A MULTIMETER SET TO THIS MODE TO CHECK FOR A BAD IGNITOR
WHAT IS OHMS?
THE MAIN CONTROL CENTER OF A FURNACE, OFTEN WITH DIAGNOSYIC LED'S
WHAT IS THE CONTROL BOARD?
THIS SAFTEY DEVICE TRIPS IF FLAMES ROLL OF THE BURNER AREA.
WHAT IS THE FLAME ROLLOUT SWITCH?
how many screws does a vent pipe require to secure it
3 for code
IF THE BLOWER RUNS CONTINOUSLY WITH NO HEAT, IT MAY BE DUE TO THIS TYPE OF LIMIT SWITCH FAULT.
WHAT IS AN OPEN HIGH LIMIT SWITCH?
WHEN TROUBLESHOOTING A TWO-STAGE FURNACE, THIS WIRE FROM THE THERMOSTAT TELLS THE CONTROL BOARD TO GO TO SECOND STAGE.
WHAT IS W2?
TWO-STAGE FURNACES TYPICALLY USE THIS TYPE OF THERMOSTAT SIGNAL TO COMMUNICATE STAGING.
WHAT IS W1 AND W2 THERMOSTAT TERMINALS?
how do you verify thermostat is bad
jump call for heat or cool
Y or W
what tool is needed to check gas pressure
WHAT IS a manometer
WHEN DIAGNOSING ERROR CODES, ALWAYS CHECK THIS DOCUMENT FIRST FROM THE FURNACE MANUFACTURER.
WHAT IS THE INSTALLATION OR SERVICE MANUEL?
what does Y mean on control board
cooling