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Why Won’t My Furnace Stay Lit?


When you switch on your heat on a cold Chicago winter day, you expect warmth and comfort. When you get nothing, you need to get to the bottom of the problem quickly. Furnaces work based on the principle of combustion, and that requires a constant source of flame. In the modern furnace, that is in the form of a pilot light. There are many components that make the pilot light work, and when they don’t function properly, your furnace won’t stay lit.

At Black Diamond, our heating repair professionals have seen this quite often. Here are some common problems that can lead to a pilot light not staying lit.

Malfunction of the Burner

The burner provides heat output for your furnace. If the burners are not working as they should, they won’t generate heat properly. If you suspect this problem, check the burners to see if they look dirty. They can become caked with carbon, which will prevent them from working well. Gas lines can also become blocked, in which case they will not send fuel to the burners.

Thermocouple Problems

If your natural gas furnace has a pilot light, the furnace will only work if the light continues to burn. The thermocouple is a part of this process. This part is a heat sensor that controls the gas valve that runs to the pilot light. It works by closing the gas when the pilot light goes out, so the home is not flooded with gas. The thermocouple senses heat from the pilot light flame, closing the valve if the light goes out to prevent a catastrophe.

So what happens when the thermocouple breaks? If it can’t sense the heat from the pilot light, it will assume that the light is out and close the valve. Without gas, the pilot light will go out, and the furnace will not function. This is, perhaps, the most common problem that causes the thermocouple to malfunction and is a fairly easy fix with the help of a skilled HVAC team.

Blocked Pilot Tube

Finally, check the pilot tube. If it becomes blocked or gets dirty, it will cause the furnace to not stay lit. Either clean the tube or call a professional to help you unblock the tube, so the light will work again.

Schedule Furnace Repair in the Crystal Lake, IL Area with Black Diamond

If you are having any of these problems, give the team at Black Diamond a call. We will come to your Chicago area home and inspect the furnace. After we find the issue, we will provide an effective repair option to get things back up and running quickly.

Give us a call today at 815-444-0979 or contact Black Diamond online to learn more about our furnace repair services.

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