From drafty chimneys to leaking faucets, many things in our homes make strange sounds that we grow accustomed to over time. Some, like the sound of water running through a pipe, are normal and we should take comfort in the fact that our homes are running normally. But when it comes to natural gas and propane lines, there are a few non-standard noises that you should pay attention to when you hear them. Strange noises and smells can be warning signs and may require immediate attention.
Hissing or Whistling
Out of all possible noises, this is the most common. While there’s some hissing whenever gas is moving through the pipes, heavy hissing or whistling when gas is not being used is a dangerous problem. That sharp hissing noise is the sound of gas escaping from the pipes. Normally that only occurs when gas is being fed to a furnace or pilot light, but it also sounds when gas is escaping from a joint, seam, or hole. If you suspect a leak, either from a gas alarm, foul smell, or loud hissing, shut off your gas main line and consult a professional for repair.
Then again, you may hear hissing coming from your propane tank outside. If this is the case, check the bleeder and relief valves. The bleed valve may have been left open and, if it was, should be closed. If the noise is coming from the relief valve, or the relief valve cap has come off, don’t worry. The relief valve is doing its job and should not be closed. This helps to prevent excess pressure from building up inside the tank due to temperature and barometric pressure changes.
Pinging or Knocking
When gas lines, tanks, or appliances give you a pinging or knocking sound, it’s likely due to problems with the air/gas mixture. When this mixture is uneven flow in the gas lines will not move evenly (similar to the water hammer noise you can get when there’s air in the plumbing). One way to check this is by looking at your furnace or a gas stove. If the flames are mostly yellow or white-blue instead of being blue with a yellow tip, then there’s an air-mix problem and you should call a professional to repair the line.
Overfilling a tank will sometimes cause a strange gurgling sound when the gas turns on. This over-pressure puts extra force on the gas-flow regulator, making it difficult for the regulator to control gas flow. A visual cue that this is the problem is in weak flames, low heat, or discolored pilot lights on gas appliances. It’s best to contact your propane supplier or a gas professional since relieving excess pressure is a dangerous business.
Humming noises share a lot of similarities with gurgling. Air that’s become trapped in the line can generate a loud humming sound as gas moves around it to get to your appliances. It’s not dangerous but it is annoying. A simple line flush will clear it out. While you can get used to the sound, that’s dangerous because it can lead you to ignore other possible problems.
Humming noises can also come from regulator issues. If you only hear humming around the gas regulator for your tank, it’s likely that the diaphragm being used is generating the noise. Restricting the gas flow or having it replaced should fix the humming noise.
This is different from pinging or knocking noises. If you hear a loud, physical clanking or impact noise, then it’s likely that the level-measurement float inside your tank has come loose and is knocking around inside your tank. Swapping out the tank is usually the best recourse for fixing this problem.
Of course, if you ever smell gas or strange odors accompany a hissing noise, the best recourse is to shut off the gas and get out of your house. Call a professional to come look at your gas lines. It’s always better to play it safe.
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