How to troubleshoot Furnace: 7 Quick fixes when it stops working overnight

Imagine you’re sleeping comfortably, and in the middle of the cold night, your furnace stops working. How do you nail this crisis? You might go for a DIY approach to temporarily fix this issue, but sometimes DIY is unable to deliver the desired result. So, to prevent costly repairs or replacements, call a skilled HVAC and let them resolve professionally.

In this guide, you’ll learn the common causes of furnace failure, offer a step-by-step furnace troubleshooting process, and outline the safety precautions you should keep in mind.

Common Causes of Furnace Failure

To solve the furnace issue, it is important to learn about the cause first. Here is the list of reasons that may cause furnace issues:

Dirty Flame Sensor

A dirty flame sensor can cause the furnace to shut off prematurely, as it fails to detect the flame properly. It commonly happens when the furnace is outdated or poorly maintained.

Clogged Furnace Vents

Blocked vents restrict airflow, causing the furnace to overheat or shut down entirely. Excessive accumulation of dust, debris, or buildup is a common reason that causes problems.

Ignitor Problems

If the ignitor fails, the furnace won’t be able to light, leaving your home cold. Internal breakdown or electrical malfunction is the ultimate reason that causes ignitor problems.

Failing Furnace Blower Motor

A malfunctioning blower motor can prevent warm air from circulating throughout your home. The furnace could be blown down or shut off completely due to overheating.

Furnace Fails to Turn On

Sometimes, the entire furnace won’t turn on due to electrical issues, a tripped breaker, or a malfunctioning thermostat. So, it’s pivotal to call an HVAC technician to handle an electrical issue.

Light the Pilot Light

For furnaces with a pilot light, the flame may go out due to drafts or a faulty thermocouple, leaving the furnace inoperable.

Strange Noises

Strange noises like banging, screeching, or rattling often signal mechanical issues or loose components in the furnace.

Step-by-Step Troubleshooting Process

Once you learn the cause that creates a problem, here is a step-by-step guide to troubleshooting the furnace problem:

Check the Thermostat

In this first step, ensure the thermostat is set to “heat” mode and the temperature is higher than the room temperature. Check batteries and change them if necessary.

Inspect the Power Supply

Check whether the furnace receives the required power or not. Check the circuit breaker for tripped switches and turn the power switch ON to streamline power.

Examine the Pilot Light

Ensure your furnace has a pilot light, ensure it is lit. If not, follow the manufacturer’s instructions to light the pilot light safely. If it doesn’t stay lit, the thermocouple may need replacement.

Clean the Flame Sensor

A dirty flame sensor can be cleaned using a soft cloth or fine-grit sandpaper. Turn off the power and gently remove the sensor for cleaning.

Clear Clogged Furnace Vents

Inspect vents for dust, debris, or obstructions. Clean them thoroughly to restore proper airflow. If external vents are blocked by snow, clear the area around them.

Check the Ignitor

If the furnace still won’t ignite, the ignitor may be damaged. Look for cracks or signs of wear, and replace it if necessary.

Test the Blower Motor

A failing furnace blower motor can prevent heat distribution. Turn the thermostat fan to “on” mode and listen for motor noises. If still does not work, call a professional and let them handle it efficiently.

Safety Precautions During Troubleshooting

Before diving into furnace troubleshooting, prioritize safety to avoid accidents or damage.

Turn Off Power and Gas

Always switch off the power to the furnace and shut off the gas supply before inspecting or repairing any components.

Avoid Open Flames

While using a gas furnace, avoid turning the lighter or matches near the furnace to check the gas leaks. It might cost your life, so avoid it.

Wear Protective Gear

Use gloves and safety glasses to protect yourself from sharp edges or debris. Take precautionary measures first and then do rectification.

Follow Manufacturer Guidelines

To deal with particular troubleshooting, read manufacturer guidelines and follow them thoroughly to prevent costly repairs.

Proper Ventilation

Work in a well-ventilated area to prevent exposure to carbon monoxide or other harmful gases. Seal the leaks with static tape.

Conclusion

A furnace breakdown on a cold night can be stressful, but understanding common issues and following a systematic furnace troubleshooting process can often restore warmth quickly. By addressing problems like dirty flame sensors, clogged furnace vents, and ignitor problems, you can resolve many issues without needing immediate professional assistance. To book your furnace maintenance service, contact us right away!

FAQs

Why did your furnace stop working overnight?

There are several reasons your furnace might fail, including a dirty flame sensor, clogged vents, a malfunctioning blower motor, or thermostat issues.

How do you know if the flame sensor is dirty?

A dirty flame sensor often causes the furnace to turn on briefly and then shut off. You may also notice your furnace cycling on and off frequently without heating your home.

What should you do if the furnace won’t turn on?

Start by checking the thermostat settings, ensuring the power supply is intact, and verifying the gas valve is open.

Is it safe to clean a dirty flame sensor yourself?

Yes, cleaning a flame sensor is generally safe if you follow precautions. Turn off the power to the furnace, remove the sensor carefully, and clean it with a soft cloth.

When should you call a professional for furnace repair?

Call a professional if your furnace continues to malfunction after troubleshooting, detect a gas leak, or blower motor damage.