December 14, 2023

Furnace Flame Sensor Problem: Understanding and Resolving Issues

Learn about common furnace flame sensor issues and get expert tips for homeowners on how to fix them.

Experiencing issues with your furnace can be daunting, especially during the cold season. A common culprit is often the furnace flame sensor, a critical component ensuring safe and efficient operation. Let's dive into the workings of a high-efficiency furnace flame sensor, common problems, repair solutions, and how HVAC-Group, your local HVAC company in Mississauga, can assist you.

What is a Furnace Flame Sensor and How Does It Work?

The furnace flame sensor is a safety device designed to detect whether the furnace's burner is properly lit. It prevents the furnace from releasing unburned gas, which could be hazardous. The sensor, typically a rod made of metal, sits in the path of the flame and detects heat. When working correctly, it signals the furnace's control board to keep the gas valve open, maintaining the flame.

Common Furnace Flame Sensor Problems

1. Dirt and Grime Accumulation

Over time, the flame sensor can accumulate dirt and grime, impairing its ability to detect the flame accurately. This can cause the furnace to shut off prematurely.

2. Misalignment

If the sensor is misaligned, it might not be in the correct position to sense the flame, leading to similar shutdown issues.

3. Wear and Tear

Like any component, the flame sensor can wear out over time, necessitating replacement.

Diagnosing and Repairing Flame Sensor Issues

- Cleaning the Sensor

A simple but effective repair is cleaning the sensor. This involves turning off the furnace, locating the sensor, and gently cleaning it with a fine abrasive pad.

- Adjusting the Sensor

If misalignment is the issue, repositioning the sensor so that it's properly exposed to the flame can resolve the problem.

- Replacement

In cases where the sensor is beyond repair, replacement is necessary. This involves selecting the correct sensor for your furnace model and replacing the old one.

Cost and Professional Assistance

The cost of repairing a furnace flame sensor varies. Cleaning or adjusting the sensor can be a relatively low-cost DIY project. However, sensor replacement might range from $120 to $250, depending on the furnace model and labor costs.

HVAC-Group: Your Local Solution in Mississauga

HVAC-Group, based in Mississauga, specializes in furnace repair, including flame sensor issues. Our licensed technicians are experienced with all known brands of residential furnaces. We offer comprehensive furnace service, ensuring your heating system operates efficiently and safely.

You can learn more about our Furnace Repair Services here.

Contact Us

Don't let a faulty furnace flame sensor leave you in the cold! Contact our professional HVAC team at 416-807-2752 or fill out our service call form on the website. We guarantee high-quality, affordable and reliable furnace repair services in Mississauga. We'll help solve your furnace issues so that you can keep your home warm and cozy!


Phone: (416) 807 - 2752
Address: 1767 Branchwood Park,
Mississauga, ON L4W 2E5