Hi! I’m Blair Gilbert, a.k.a.
As a third-generation hardware store owner, licensed builder, and finish carpenter, my mission is to help you “do it right the first time!” On this site, I share expert home and yard DIY advice in over 250 articles and videos. Feel free to dive in!
- Read furnace error fault code lights to repair, troubleshoot, fix, diagnose (3/11/2019)
The error code tells you what sensor has tripped. It does not tell you why the fault. Do not blame the code sensor light unless you are positive it is the sensor that has failed.
Thermostat malfunctions are most common heating system failures so check the switches, settings and loose or broken connections. Other reasons are tripped circuit breaker, blown fuse, combustion furnace pilot light.
The furnace diagnostic code lights can be seen through the furnace window or when the front panel is removed.
Different furnaces have different patterns. For example, maybe the light codes are 2 digits – the number of short flashes is 1st digit of the two digit fault code. The number of long flashes of the LED is the second digit of the fault code. A steady burning LED light means normal furnace operation.
Or it means something if the blinking is slow or fast. Like the green light is blinking slowly means the furnace is on but there is no request for heat. A continuous light means that the circuit control board needs replacement, but completely off means the furnace is either off or not receiving electrical power.
If a code refers to gas, ignition failure, or flame proving failure, the problem is the burner assembly area, like the igniter or flame sensor is either bad or dirty.
An oil furnace not coming on may show a red light lit on the burner unit. When on, this red lockout light indicates you are shutdown due to a problem or fault for safety.
A furnace blower motor that stops pushing any air is broken. If there is a steady flow of cold air, the blower is good, but your heat exchanger or burner is not, and inspect for cracks and leaks.
Why does my furnace turn on and off? It could be the flame sensor is dirty.
But the most common cause for your furnace to keep turning on and off is the High-Limit Switch, which turns the unit off if the temperature inside gets too high, as a precaution. This is most common cause of short cycling. A dirty air filter restricts air from getting into your furnace. Your furnace’s heat exchanger needs that air blowing over it or it overheats, causing the furnace to shut down. So, change it!
More New Articles
- Furnace General Aire Gage, media filter air pressure gauge (2/25/2019)- The furnace General Aire Gage media filter air pressure gauge shows when you need to replace the air filter in your forced air heating and cooling systems. The gauge is placed between the… ...read more
- Garage door winter cold keypad fix, replace, new code, repair or clean contacts (2/11/2019)- Repairing a garage door opener keypad is easy enough. You may have to try different solutions to fix the problem. Start the garage door opener keypad repair by looking over the manual for… ...read more
- Install flow-through furnace humidifier in 1 hour, save $200 and replace old drum reservoir humidifier (1/28/2019)- Flow through-humidifiers are replacing the older drum humidifiers in recent years. This is mainly due to tighter houses. The disadvantage to a drum is that standing water present in the reservoir allows bacteria… ...read more
- Drum humidifier float repair, replace to fix overflow on furnace (1/14/2019)- Drum or reservoir humidifiers use a rotating drum-styled foam pad or similar media that picks up water for evaporation from a float-controlled reservoir. These types are the most prone to mold problems, due… ...read more
- Tips for painting laminate kitchen cabinets, preparation, BIN primer, acrylic latex (12/31/2018)- Painting laminated cabinets and doors requires critical preparation, cleaning, sanding and priming. We like TSP or a degreaser and it must be thoroughly rinsed from the surfaces so the primer will adhere. Then… ...read more