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York Furnace Not Igniting or Lighting? 4 Common Causes

York furnaces are great at keeping your home and family warm during the winter months. But if your York furnace isn’t igniting, you’ll be left with a frigid home and a dozen questions. Thankfully, identifying the source of the problem is simpler than you think.

Your York Furnace isn’t igniting or lighting because of a dirty flame sensor, stuck gas valve, faulty ignitor, or bad control module. You can fix the problem by cleaning the flame sensor, opening the gas valve, and inspecting and replacing the ignitor and control module.

If your York furnace isn’t igniting, you came to the right place. Read the rest of this guide to identify the reason behind the failed ignition. I’ll also tell you what needs to be done in each scenario.

Dirty Flame Sensor

One of the most common reasons behind a York furnace not igniting lies with the flame sensor. If this is the case, something as simple as cleaning this part of the system will resolve the issue. The thing is, people often start with some of the more serious causes that may require taking multiple parts out of the furnace. 

Instead, start by checking the flame sensor. It’s a relatively small piece of equipment in the furnace, yet when debris starts packing up on the rod, it will cause ignition problems. The rod is made to be durable, but the sensor can crack over time, especially with excessive stress put onto it. This is another potential fault you should consider while cleaning the flame sensor.

How To Fix

To clean the flame sensor, start by getting into the furnace. Use a screwdriver to remove the panel and look at the combustion chamber. You’ll see a small metal rod sticking out of the chamber. That’s the flame sensor. Here’s what to do next:

  1. Use the right tools to loosen the flame sensor, then remove it from the combustion chamber. 
  2. Use a small brush to remove debris. 
  3. If you see a thick layer of soot, get a piece of fine-grit sandpaper. Use the sandpaper to remove the debris, then blow over the rod to remove the particles.
  4. Put the rod back into the original position and fasten it again. Be careful as you don’t want to crack the rod.

The video below will help you clean your York furnace flame sensor:

Stuck Gas Valve

During the start-up process, the gas valve needs to open up. As the valve opens, the gas pushes through the furnace and toward the ignitor. Once gas reaches the ignitor, the device kicks in and creates a spark leading to ignition. 

Sometimes, the gas valve can get stuck. And when it’s stuck, gas cannot pass through. This means ignition will fail. Sometimes, a small amount of gas manages to pass through, but ignition is still likely to fail, or the flames won’t be sustained.

When the gas valve is stuck, you may hear a clicking sound when you turn on the furnace. This is the ignitor trying to do its job — but with no gas coming into the burner, the spark from the ignitor can’t create a flame. Since the flame sensor isn’t detecting a flame, the ignitor keeps trying to spark a flame. 

How To Fix

You need to investigate the gas valve to determine why it’s not opening up. When you start the furnace, a signal is sent to the gas valve, instructing it to open up,  allowing for ignition to occur. 

Here’s what you have to do:

  1. Identify the location of the gas valve. It’s connected to the gas supply line and can be found inside the furnace. You need to take off the main panel to access the valve. 
  2. Look at the physical structure of the valve. Take notice of any damage. You can use a picture of a gas valve found in a manual or online to compare the appearance. 
  3. See if anything is obstructing the valve. If this is the case, the obstruction may make it impossible for the gas valve to open up in the queue. 
  4. Remove any obstructions. If the valve is damaged, you need to replace it before opening it up properly. 

The video below helps you replace the gas valve in your furnace:

Faulty Ignitor

The ignitor is responsible for lighting a flame inside the furnace. When this part of your HVAC solution is faulty, it can’t start a flame, which means ignition will fail, and your home won’t get any heat at all. 

Various problems can occur with an ignitor. Newer furnaces use an electric ignitor, which creates a spark using electricity. Older systems use what is known as a pilot light.

No clicking noise during the start-up process signals a potential problem with the ignitor. If the ignitor isn’t at fault, you should hear a clicking noise as it’s creating sparks to ignite the gas. 

How To Fix

Before replacing the ignitor, you need to ensure that’s what’s causing the problem. Ignitors can be pricey to replace, so you want to be absolutely sure.

If there is no clicking sound, maybe the ignitor isn’t receiving any power. You can use a multimeter to test the ignitor’s voltage. If you get a low reading, the problem likely lies with your power supply or the control boards involved in distributing power throughout the system. 

Here’s a video that will teach you how to replace a furnace ignitor:

Bad Control Module

Another potential problem may lie with the control module. The control module is a small circuit board programmed to provide electricity to the ignitor and other parts. 

You need a multimeter to test the control board. A visual inspection can also help. This two-step process will help you identify potential problems with this component, allowing you to determine if a replacement is needed. 

How To Fix

Start with a visual inspection of the control module. Open your furnace and locate the control module. Make sure all connections are secure — there should be no loose wires. Look for signs of damage, such as dark spots that indicate burn damage. 

Use a multimeter to determine if power is supplied to the control board and see if there is an output of power. This will help you see if power is lost somewhere on the board. 


A dirty flame sensor, a stuck gas valve, problems with the ignitor, and issues with the control module can cause a York furnace not to ignite. You can fix most of these issues yourself, but it’s sometimes better to call an expert.