The last thing you need in the middle of a frigid winter night is for your home's gas furnace to stop working. Unfortunately, furnace problems rarely present themselves at "convenient" times. For gas furnaces, many heating problems can be traced back to issues with the pilot light and/or gas supply. By knowing how to do some basic troubleshooting on your furnace's pilot light, you can get a better idea of what the problem might be and determine when to call a furnace repair contractor.
The Pilot Light Is Off
If you don't have heat at all, the pilot light is one of the first things you'll want to check by removing the front panel to your gas furnace. If the pilot light is completely off, there are a few potential causes. Start by attempting to re-light the pilot following the instructions provided in your furnace manufacturer's manual. If that doesn't do the trick, or if the light will not stay lit, you may be dealing with a broken thermocouple that will need to be replaced by an HVAC professional. If the pilot will not re-light to begin with, check the thermocouple for dust and debris buildup, as this can prevent the pilot from lighting. Wiping the thermocouple clean may do the trick.
The Pilot Light Is Yellow
Ideally, your furnace's pilot light should burn a blue color (possibly with a slight yellow tip). If the flame appears to be mostly yellow, this is usually a sign that an air intake valve is clogged somewhere. This is something that should be addressed by a professional furnace repair contractor as soon as possible, as clogged air intakes can result in a buildup of carbon monoxide--which can be dangerous to your health.
The Pilot Light Is Flickering
If your pilot light is on but seems to be weak or flickering, this is usually a sign that there is not enough gas getting to the pilot light's fuel reservoir. This probably won't affect your furnace's performance significantly, but it can lead to your pilot light burning out over time. With this in mind, it's best to schedule a service call to have a furnace repair contractor to resolve the problem sooner rather than later.
Dealing with gas furnace issues can be a headache, but the good news is that many problems with furnace pilot lights are relatively easy to troubleshoot and resolve yourself. If all else fails, you can always rely on your local furnace repair professional to get to the bottom of the issue.