If your gas pilot light won’t stay lit, it can be a big, and sometimes dangerous problem. This problem can be caused by a variety of faults and issues such as a dirty or blocked pilot orifice, a weak or faulty thermocouple, low gas pressure, air in the gas line, or an incorrectly adjusted gas valve.
In this article we go over the most common reasons your gas pilot light wont stay lit, and how best to fix it.
Possible Reasons Why Your Pilot Light Wont Stay Lit
Incorrect Lighting Procedure
If your pilot light goes out immediately after lighting it, it could be as simple as not following the correct procedure. On most appliances (gas furnace, hot water, heater) there should be a label that goes over the correct procedure to light the pilot light.
Ensure you follow this procedure and do not deviate from the instructions.
The thermocouple is a safety device that is designed to stop unburned gas from accumulating within the appliance and causing a possible explosion. If the thermocouple rod does not sense enough heat, then it will not allow the pilot light gas valve to open.
So if the thermocouple goes faulty, then it will cause the pilot light to either not stay lit, or to not light at all.
It is likely that you will need to call a professional to fix this problem as to to check if the problem is a bad thermocouple rod, it will need to be tested with a thermocouple tester. This device will measure the voltage being produced by the thermocouple and can determine if the rod is working correctly. If it is not, then the thermocouple rod should be replaced in order to ensure the pilot light remains lit and the gas valve is operating properly.
Following on from the last issue, a dirty thermocouple rod can also cause intermittent problems with the pilot light.
A thick layer of carbon on the outside of the thermocouple rod can act as an insulator, preventing the correct amount of heat from reaching the thermocouple.
This problem can be solved by cleaning the rod with unsoaked steel wool, but you need to be very careful not to get any pieces of the steel wool in the pilot tube. If you can, remove the thermocouple rod from the pilot light assembly to clean it.
Once again you may be better to call a professional to sort this one out.
Incorrect Thermocouple Rod Position
Check the position of the thermocouple rod in the pilot light assembly. If it has slid down in the bracket, or the bracket is not holding it in the right place then it may not be sensing the heat as it should – causing the valve to be shut and the pilot light to go out.
The rod itself should be in the flame of the pilot light. It it isn’t, then this can cause the pilot light to go out.
Loose Thermocouple Connection
The thermocouple connects to the bottom of the gas valve via metal tube connection. If this is loose then it will not allow the thermocouple to open the gas valve – once again causing the pilot light to go out.
Low Gas Pressure
If the gas pressure to your appliance is too low then it could be causing the pilot light to be simply to small to activate the thermocouple, which in turn stops the pilot light from igniting. If this is the case, you will likely need a professional to help you solve the problem.
Clogged Pilot Tube
A clogged pilot tube can prevent the gas from flowing to the pilot light, causing it to go out. This can be caused by debris, dust, or insects that have made their way into the tube.
If you suspect that either of these is the problem, unscrew the pilot tube from the pilot termination and also from the valve. Ensure that the tube is not kinked and give it a good blowout with some compressed air. You can also attempt to clean out the pilot light assembly, but be careful not to damage it.
An alternative is to replace the pilot light assembly and tube altogether.
Bad Gas Valve
A bad gas valve can prevent the gas from flowing to the pilot light, causing it to go out. This can be caused by a malfunctioning solenoid or a valve in the gas regulator that is not properly adjusted. Replacing the gas valve can solve this issue.
Manual Gas Valve Is Off
The appliance should have a manual gas valve on the gas inlet pipe. If this valve is closed, then the pilot light will not ignite. Double check the manual valve and ensure it is open.
Drafts and Wind
A draft can cause the pilot light to go out because it can blow the flame out of the pilot tube. This can be caused by open windows or doors, or a chimney that is not properly sealed. Closing the windows or doors, or sealing the chimney can solve this issue.
Blockages In The Pilot light Tube
Blockages in the pilot tube can cause the pilot light to go out. This can be caused by debris, dust, or insects that have made their way into the tube. Cleaning the tube can solve this issue.
Incorrectly Sized Gas Orifices
The orifices that control the gas flow to the pilot light can be incorrectly sized. This can cause the pilot light to go out because the gas flow is not sufficient to keep the flame burning. Replacing the orifices with the correct size can solve this issue.
A worn thermocouple can cause the pilot light to go out because it is not sending the correct amount of heat to the thermocouple inside the outer rod. Replacing the thermocouple can solve this issue.
Improperly Adjusted Pilot Light
The pilot light can be adjusted too low or too high, causing it to go out. This can be caused by a knob that is not properly adjusted or a valve that is not properly adjusted. Adjusting the knob or valve can solve this issue.
Leaks in the gas line can cause the pilot light to go out because the gas is not flowing through to the pilot light assembly correctly. This can be caused by a damaged or broken gas line, or a valve that is not properly sealed. Replacing the damaged or broken gas line, or sealing the valve can solve this issue.
Other Problems With Your Pilot Light
While some issues that cause a gas pilot light to not stay lit can be easily diagnosed and fixed by the homeowner, others may be more complex and require the expertise of a professional. It is important to be aware that working with gas can be dangerous, and if you are not comfortable or familiar with the process, it is best to call a qualified professional.