Furnace Does Not Turn On?
You may be able to fix it, or you may need a qualified HVAC technician. There’s a few simple causes you can diagnose and correct yourself before you call a professional to review your heating system. Let’s do over them together.
Why Your Furnace Won’t Start: The Easy Causes You Can Fix
Dead Batteries in Thermostat
Let’s start with the easiest and most obvious. Some folks seem to think that since the thermostat is wired to the furnace, that’s the power source. With connected homes nowadays, it’s not uncommon thermostats require an independent power source. Check to see if your thermostat uses batteries, and if they still have juice.
Broken Thermostat
A malfunctioning thermostat can be the problem source. Most digital thermostats show an error code when something goes wrong. You can check the code to see if a simple fix, like a reset, will resolve the issue. While you might be able to handle the replacement yourself, it’s a good idea to consult an experienced HVAC technician if you’re unsure about working with electrical components
Gas Turned Off
This is another simple one that some folks miss. For instance, they move into a new home, and forget to transfer the gas into their name. A simple way to test is to check the gas lines, is if the gas oven burners turn on. If you have gas coming into the stove, it should be coming into the furnace.
No Pilot Light
For older furnaces that use pilot lights, this is the next obvious solution. Sometimes a random gust of wind can knock out a pilot light. When relighting the pilot light, do not wait for a big gas build up. Pilot lights as a furnace starting mechanism hasn’t been used for decades, but there are still older furnaces out there using this lighting mechanism.
Blocked Ducts
This can be another easy one to overlook. Ducts can be toy-magnets for toddlers, with balls rolling way back and stuffed animals seemingly coming to life and crawling deep into ductwork.
Dirty Air Filter
Over time, dust, hair, pet hair, and other debris accumulates in the filter, reducing the furnace’s efficiency. At some point, the furnace is starved of air flow. Then, every furnace is equipped with limit switches activating when the temperature exceeds a certain threshold, shutting the furnace down to prevent danger and damage.
To locate the filter, find the area where air enters the furnace. Slide out the old filter and check the side for its model number and size to ensure you purchase the correct replacement. When replacing the filter, look for an arrow on the frame indicating the direction of airflow. When inserting the new filter, make sure the arrow is pointing toward the furnace.
Thermostat Turned Off
This is an easy on. Sometimes folks forget the simpliest reason. Check that your thermostat is set to the full on-position.
Flipped Breaker (reset only once)
If your breaker flipped, it’s for a reason. Resetting the breaker once is OK, but if the breaker flips a second time, that means there’s an underlying issue. For safety reasons, reset a power switch only once.
When to Hire Nordstrom Heating To Fix Your Furnace
Dirty Flame Sensor
A dirty flame sensor on a gas furnace is a common issue causing problems with ignition and operation, which prevents your furnace from unsafe operation. The flame sensor is a small, metal rod near the burner, detecting the presence of the flame when the furnace ignites.
Breaker Keeps Tripping
Though it may be tempting to keep on resetting, a frequently tripping breaker is a sign of a more significant issue in need of attention. There’s plenty of reasons why a furnace breaker keeps popping. If other appliances are sharing the same circuit as your furnace, such as like space heaters or high-wattage lights, it can overload the circuit. Overloaded circuits can also be caused by faulty wiring, such as loose connections or short circuits. A dirty air filter restricts airflow, forcing the furnace to work harder and draw more current. A seized or malfunctioning blower motor can draw excessive current. Issues like short circuits or faulty components within the furnace itself can trip the breaker.
Safety Features Triggered
Safety features are critical, not to be ignored. Common safety features are:
- Flame Sensor: This sensor constantly monitors the flame.
If the flame goes out unexpectedly, the sensor immediately shuts off the gas supply preventing gas buildup and potential explosions. - Rollout Switch: This switch detects if combustion gases are backing up into the living space instead of being properly vented. If this occurs, the switch shuts down the furnace, preventing carbon monoxide poisoning.
- High-Limit Switch: This switch monitors the temperature of the heat exchanger.
If it overheats, the switch shuts down the furnace to prevent a fire hazard. - Pressure Switch: This switch monitors the pressure of the air flowing through the furnace.
If the pressure drops too low, it indicates a problem with airflow, and the switch shuts down the furnace to prevent overheating. - Draft Inducer Motor: This motor helps to ensure proper venting of combustion gases.
If the motor fails, the furnace will shut down. - Gas Valve Safety Controls: These controls prevent the flow of gas unless the ignition system is properly functioning and the flame sensor confirms a stable flame.
Capacitor Fails
Capacitors fail for a variety of reasons, including:
-
Aging: Like most electronic components, capacitors have a finite lifespan.
Over time, the internal components can degrade, leading to reduced performance and eventual failure. -
Overheating: Excessive heat can significantly shorten the lifespan of a capacitor.
-
Environmental Factors: Exposure to moisture, extreme temperatures, and vibrations can also contribute to capacitor failure.
Furnace Blower Motor Issues
Several factors can cause a furnace motor to stop working:
- Burned-out windings: The motor’s internal wiring can overheat and burn out due to excessive current, voltage surges, or short circuits.
- Overheating: Excessive heat can damage motor components.
This can be caused by restricted airflow (dirty air filter, blocked vents), overheating of other furnace components, or a malfunctioning thermostat. - Mechanical Issues: The motor shaft can become misaligned or damaged, preventing proper rotation.
Furnace Door Does Not Shut Tight
Furnace doors contain safety switches. If the furnace door is opened, the switch disengages, immediately shutting down the furnace. This prevents:
- Accidental exposure to heat or flames: Opening the door while the furnace is running exposes you to the risk of burns.
- Promote intermenacy in how the furnace gets power.
You Smell Gas
This one is a biggie. Luckily, it’s also obvious. Natural gas is scented with a rotten egg smell, so you immediately notice and want to remediate.
Electrical Components
The electrical board within a furnace is the central control hub, coordinating the operation of all components, ensuring a safe and efficient operation. When a board goes out, it’s best to have a pro replace.
Furnace Still Not Starting?
Call us at 360-386-8770. Let’s have a conversation together. We can determine what the problem may be, discuss furnace repair, and appropriate next steps.
