Over time, the thermocouple can wear out, get bent, or become covered in dirt, preventing it from detecting heat correctly. If dust, soot, or debris is clogging the pilot tube (the small pipe that delivers gas to the pilot light), the flame either won't ignite or it will be weak and unstable.
If your pilot is lit and the fireplace isn't igniting when you push the button or flip the switch, the igniter may be dirty or defective. Clear away any dirt or debris that may be in the way between the igniter and thermocouple or thermopile.
Dirt, dust, and debris can block the flow of gas from the pilot tube. This means that the pilot light isn't receiving enough fuel to fully ignite. Thankfully, fixing this issue is easy -- all you need is a long needle and a bit of patience. Gently poke the needle into the pilot hole and remove any debris.
Use an electric meter on volts DC to test if the thermocouple is bad. you can also try to re-light the pilot and see if it goes on. Thermocouples can be cleaned, but this is only a short fix. The pilot will go out again over time. Thermocouples are not expensive. The best thing to do is just change it.
Common Gas Fireplace Issues and Repair Options
Relighting is typically inexpensive unless the thermocouple requires replacement, which can range between $120 and $300.
If the pilot flame ignites but goes out after you release the gas control knob, the cause may be a dirty or defective thermocouple. If the gas is on but the flame will not ignite at all, a pilot tube obstruction is the most likely issue.
If your gas pressure is too low, the pilot light may not light at all or may go out frequently. This could indicate a problem with the gas provider or a regulator issue. You may need to contact your gas provider to check your home's gas pressure or have a technician inspect the regulator.
If the pilot light is extinguished, allow at least 5 minutes for accumulated gas to disperse after turning off the gas valve before attempting to relight the pilot. Follow manufacturer's specific instructions for relighting the pilot after the gas has dispersed.
One of the most common problems faced by homeowners with gas fireplaces is the pilot light going out or not staying lit. The pilot light is a small flame that ignites the gas burner, which produces the heat for your fireplace — if the pilot light goes out, your fireplace won't work.
Press and hold the reset button. If the reset button fails, ignite the lighter. Hold down the reset button and bring a grill lighter or long match to the pilot light valve until the pilot ignites. Once the pilot light stays lit, turn the valve to the “on” position.
Short cycling is a common sign of a bad flame sensor. The sensor thinks that there isn't a flame, so it shuts off the gas as a safety mechanism. Except, there is a flame and without the gas to supply it, it dies. This is a frustrating problem, but an HVAC technician can fix it.
Using a long match or long-barreled lighter, press and hold down the gas control knob with the lit match or lighter until the pilot lights. The pilot should start immediately once the flame is close enough.
Clean the thermocouple - using the emery cloth sandpaper, sand the ends of the thermocouple and then give it a finishing touch with the lint-free cloth. Hopefully, you can get to the ends of the thermocouple without having to detach it from the assembly, but you may have to do that.
Symptoms Pilot won't light. Pilot lights but burner won't. System lights, but goes out after a while.
Check the Spark Igniter
If gas is coming out of the pilot but it still won't light, the spark igniter could be the problem. You should clear out any debris between the igniter and thermocouple. Blow compressed air into the pilot area, wait a couple of minutes, and then try again to see if this fixes the problem.
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.
There's really no set lifespan for a thermocouple. They typically last for the life of the water heater itself, which may be anywhere from 10 to 15 years.
While pressing and holding in the black knob, press the RED igniter button repeatedly; the pilot will generally light with two or three pushes on the igniter. 4. Once the pilot is lit, continue to hold the valve knob in for 30 seconds, then release the knob and it will pop back out. The pilot should remain lit.
It's easy to replace, and a new one costs $5 to $10. Rather than trying to unfasten the thermocouple inside the water heater's burning chamber, it's easier to remove the whole burner and thermocouple assembly.
Common Signs of a Failing Thermocouple
Here are some common indicators: Difficulty Lighting the Fireplace: If you struggle to light your fireplace, or if it takes several tries to keep the pilot lit, it could suggest that the thermocouple is not sensing the flame correctly and is failing to keep the gas supply open.
The thermocouple is a safety device designed to shut off the gas valve if the pilot light goes out. Although, if your thermocouple is old, worn, damaged, wrongly positioned, or malfunctioning, it could have wrongly shut off the gas valve and prevented your pilot light from staying lit.