If your gas furnace works on a pilot light system, then the flame and the way it works can give you an early heads-up that your furnace has a problem. Your pilot light will start working differently in line with the underlying problem.
What can pilot light changes tell you about your furnace?
1. The Burner Flame Changes Color
When your pilot light system is working correctly, it should produce a steady blue flame. This flame might have a tinge of yellow or orange at the tip, but the core color is blue.
Sometimes, furnace burners turn yellow or orange. This color change is a warning sign that you have a problem with your system. For example, the pilot light's air intake valve might be dirty, blocked, or broken. If your burner doesn't get an adequate oxygen supply, then its flame can't combust at full strength, and it won't have its healthy blue color.
While the underlying problem behind flame color changes might not be serious, you should fix this problem quickly. If a flame isn't strong enough to burn off carbon monoxide, then it could release this dangerous gas into your home.
2. The Pilot Light Goes Out
Your pilot light should stay on when you need to run your furnace. However, sometimes the light goes out for no apparent reason.
In some cases, the light starts out OK, then turns off suddenly. This can be caused by dirt in the burner that affects the gas supply flow. If this flow is intermittent, then the flame can go out if it isn't getting a strong supply. Or the gas tube might be blocked or dirty.
Sometimes, problems with the furnace's thermocouple shut down the burner. The thermocouple is a safety device that detects problems in the pilot light. It works as a flame sensor. So, if your pilot light's burner goes out or doesn't create a strong enough flame, then the thermocouple shuts down the gas supply to keep things safe. If the thermocouple is broken, faulty, or corroded, then it might do this even if the pilot light doesn't have a problem.
Pilot lights can also go off if you have dirty filters in your system. Faulty thermostats can also shut burners down. If the thermostat can't read heat accurately, then it might shut down the burner at the wrong time.
If you notice any of these problems, then call out a furnace repair service. They can diagnose the problem and repair it for you to get your furnace up and running again.