If no gas is flowing to the pilot light, you obviously won't be able to get it to light. This can happen because the furnace's main gas valve isn't fully open or if your gas supply is shut off or interrupted. There is also a chance that the pilot tube that supplies gas to the flame is clogged.
In many cases, the reason that you can't get your pilot light to ignite is that the pilot tube is clogged. This is a small metal tube that supplies the gas needed to ignite the pilot and keep it lit. The pilot tube often becomes clogged with debris, and this will prevent gas from flowing to the pilot light.
YOU EITHER NEED A NEW THERMOCOUPLE, OR THE EXISTING THERMOCOUPLE IS NOT IN THE FLAME, OR THE EXISTING THERMOCOUPLE IS ENCRUSTED WITH SOMETHING, OR WHEN YOU ARE TRYING TO RE-LIGHT THE PILOT LIGHT YOU ARE NOT HOLDING THE GAS BUTTON IN FOR A LONG ENOUGH TIME.
The flame will go out if you release the knob before it is hot. The thermocouple can become dirty and caked with grit, preventing it from heating up and detecting that the pilot is lit. As a result, the pilot will always go out after you release the reset button.
There's really just one telltale sign of letting you know when the thermocouple isn't working, and that's when the pilot light won't stay lit. If you experience this problem, it's important to have your thermocouple assessed as soon as possible.
If you try to relight a pilot light and the thermocouple is bent in a way that causes it to not make contact with the pilot light, the flame will instantly go out when you release the pilot control knob since the probe won't detect the heat from the flame.
You should not try to relight the pilot light yourself if you smell gas, hear hissing sounds from your gas line, or otherwise think that you might have a gas leak in your home. If you try to reignite the pilot while gas is in the air, it could start a fire or cause an explosion.
Turn the gas knob to “PILOT” – Hold it down while using a long lighter to ignite the pilot flame. Hold for 30-60 seconds – Keep the gas knob pressed for about a minute to allow the thermocouple to warm up. Turn the knob to “ON” – Once the pilot flame is stable, turn the knob back to the ON position.
Take a soft brush such as an old toothbrush and gently remove any visible debris from the pilot orifice, flash tubes and ignitors. Next, insert a sewing needle or thin wire into the pilot orifice, the flash tubes and the holes in the ignitors, as well as in the burners, wiggling it gently to dislodge any debris.
Call Your Local Mr. Rooter Plumber! If you are having trouble getting your water heater pilot light on, or you can't get it to stay lit for long, rely on a plumbing professional for water heater repair, maintenance, and replacement services.
Gas Flow Issues
If no gas is flowing to the pilot light, you obviously won't be able to get it to light. This can happen because the furnace's main gas valve isn't fully open or if your gas supply is shut off or interrupted. There is also a chance that the pilot tube that supplies gas to the flame is clogged.
The Short Answer Is: It is generally safe for a homeowner to relight a furnace pilot light, as long as they follow proper precautions and guidelines. To do it yourself, first, turn off the furnace's gas supply and wait for a few minutes to allow any lingering gas to dissipate.
Once you've located the thermocouple, do a visual inspection. You're looking for a few things. The first is signs of contamination on the tube, which can include discoloration, cracks, or pinholes.
Yes, you can clean a thermocouple, but the task must be done with a light touch. Remove the thermocouple from the process assembly, using a steel wool or emery cloth, lightly clean the tip removing any build up. Cleaning a thermocouple is not a fix for an issue, such as inaccurate readings.
Replacing a thermocouple is a relatively easy fix that can take less than two hours. This guide reviews how to replace a thermocouple to ensure gas appliances stay in good working order, as well as how to relight a pilot light.
If your pilot goes out, we recommend letting it sit for five to 10 minutes so any residual gas can escape from the unit. You don't necessarily have to turn the gas valve off. Just make sure the control knob on your pilot light is in the OFF position. Let it sit for a few minutes before you try to relight it.
If it doesn't have the button, or the button fails, press the regulator valve and hold a grill lighter or long match to the pilot light valve until the pilot ignites. Hold the button down for up to a minute to ensure that the light stays lit. Turn the gas regulator valve to the “on” position.
Gas Valve & Gas Supply Issues
The pilot light depends on a reliable source of gas or propane in order to stay lit. Any issues with the gas valve that supplies that gas to the flame, whether it be dirty or malfunctioning, can result in that flame going out.
Furnace Thermocouple Replacement Cost
If you're comfortable handling small furnace repairs, you can purchase a furnace thermocouple for about $10 to $20 from a hardware store or online. Replacing the thermocouple requires some basic tools and familiarity with the furnace's inner components.
The pilot flame should touch the thermocouple at a specific level. If the flame is blue and weak, and barely reaches the thermocouple, it needs to be stronger. If it extends well above the thermocouple, it's too strong.