Troubleshooting A Furnace Pilot Light That Is Not Working Correctly

If you have an older gas furnace, then it is very likely that you also have a pilot light. This light is responsible for igniting the gas fuel so that heat can be created and moved into your home. Pilot lights often work well, but when they stop working properly, then you simply do not have a heated home. This is obviously problematic, so keep reading to learn about some tips to help you get your pilot working again.

Clean The Pilot Tip

Pilot lights are fairly simple devices that involve a working tip called a pilot tip that sits at the very end of a small gas supply line. This tip is fitted with a hole that allows a very small amount of gas to escape so the pilot light can be created. This tip is also fitted with a shutoff valve, and it is connected to a thermocouple that senses whether or not the pilot light goes out. 

Since the pilot tip has such a small opening, it can become clogged with debris fairly easily. Debris can come from rust that develops on the inside of the heater, and this is a common issue that develops when a basement is damp. Also, the tip itself can corrode. Most tips are made from stainless steel, but a small bit of corrosion will form as the steel ages and the protective zinc coating wears away. 

It can be difficult to tell if the pilot tip is simply dirty or corroded. This is why it is wise to clean the tip first and then replace it if the pilot is still not working correctly. Turn off the gas to the furnace before you start and locate the pilot tip. Look at the tip to see if it is covered in a black soot. If so, then use a stiff wire brush to clear the soot away. A metal file may be needed as well if black debris remains. To clean the top opening, you will need a degreasing agent. A few different cleaners can be used, but one of the most effective is a carburetor cleaner. This heavy duty degreaser is meant to clean away the debris from automotive fuel combustion, so spray just a small amount along the opening of the pilot tip. Use a clean cloth to clear away the cleaner and the debris afterwards.

Replace The Tip

If the cleaning does not help to get your pilot light working properly, then it may be time to replace the pilot tip. This is something you can do yourself, but you do need to complete the repair carefully so that gas leaks are prevented. Also, you should understand that the pilot tip and the thermocouple are typically sold together as a set and are secured to the same bracket. Since thermocouple defects and breakages can result in pilot light issues, the complete tip/thermocouple replacement is recommended. 

With the gas off, remove the old tip and thermocouple bracket. Release the gas line from the pilot tip and gently pull the wiring harness from the thermocouple. Secure the new bracket and attached pieces in place and reattach the wiring harness. You will need to replace the gas line at this time. However, you will need to add plumber's tape to the threads of the pilot tip before twisting the line in place. 

Once you have secured the gas line, you should spread a small amount of leak detector fluid or gel around the outside edge of the seam. This material will change color if there is any gas leaking around the tip.

Once the tip is secured and you are ready to start up your heater again, make sure to adjust the flame so it is blue to ensure safety and efficiency. If this isn't a process you're comfortable doing on your own, make sure to reach out to a local HVAC service.