Why Is My Propane Tank Humming?

Propane Tank NoisesIt doesn’t matter if you’re using a portable tank or a full-size home tank, propane tanks have the same basic components (they only change in complexity as the tank gets bigger).  Whether you’re firing up the grill in your backyard or simply turning on a gas-powered appliance inside your home, every proud propane proprietor will eventually hear strange sounds coming from the appliance, the gas line, or the tank itself.  An odd noise is usually a sign of a problem so we recommend keeping an eye out for these noises for both your safety and to protect the lifespan of your equipment.

Gurgling or Humming

When you turn on the gas, if you hear a low, gurgling rumble or similar humming noise, your tank may have been overfilled.  When a tank is overfilled, it puts excess pressure on the regulator, reducing outflow from the tank.  If you’re not getting enough propane at your destination (weak flames, low heat, discolored pilot lights), it’s likely that the tank was overfilled.  We do not recommend trying to drain a propane tank yourself.  If it’s a portable unit, return it to the retailer.  If the problem is with a permanent tank, contact your propane supplier.  Releasing propane can be dangerous, so please do not attempt it yourself.

Sometimes, the regulator for your tank is the sole cause of a humming noise.  The regulation valve uses a rubber diaphragm which can vibrate under certain conditions.  When this vibration reaches it a certain level, it resonates and creates an audible humming noise.  Restricting the flow through the regulator slightly will sometimes fix this problem.

One other source of humming is trapped air.  Occasionally, a pocket of air will get trapped inside the hose.  As propane rushes around the bubble it creates an audible humming noise.  While the air bubble itself is not dangerous, the humming noise can be very loud and annoying.  You also run the risk of becoming used to the noise and ignoring other issues that develop.  A simple line purge (included in the owner’s manual for your tank) will solve this.

Pinging or Knocking

If you turn on the gas and are greeted with a pinging or knocking noise you should get the unit inspected.  These noises are usually indicative of an uneven mixture of gas and air within the tank.  If you use a propane stove, you can double check this by examining the flames generated.  With the correct mixture, they should be blue with a yellow tip.  If the color is wrong (the flames are yellow or white-blue), then you should call a technician to adjust how your tank controls air-flow.

Clanking Sound

Sometimes you’ll hear a clanking sound from within the tank as it moves around or operates.  This is different from the loud knocking previously mentioned because it has a more physical impact-based sound.  If you’re hearing this noise, the level-measurement float inside your tank has probably come loose and is knocking against the inside of the container.  Swapping out the tank is the best course of action to alleviate the noise.


Hissing is the most common noise you’ll hear from propane (and even natural gas) tanks.  Don’t confuse this for the initial gas rush you hear when you turn the line on.  Hissing usually comes from a gas leak.  Gas leaks are extremely dangerous and should be dealt with immediately.  For portable units, the problem may only be a damaged hose.  To identify if the hose is the problem, remove the hose and submerge it into a bucket of soapy water.  If bubbles form, then there is a hole in the line.  You could patch it, but it’s a better idea to simply replace the hose.

On larger tanks, a feed line may not be the cause of the hissing.  If the hissing noise is coming from the tank itself you should check the bleeder and relief valves.  If the bleeder valve was left open the last time the tank was filled, simply closing it should shut off the hissing.  The relief valve will be covered by a large plastic cap, if this cap has come off it means that the relief valve is doing probably the source of the hissing.  Do not try to close the vale and do not stare into the valve.  The relief valve is there to help with pressure release and is operating properly.  Pressure usually builds up inside a propane tank on hot days.  Cooling the tank off with a water hose should lower the pressure and allow the relief valve to close normally.

Smell and Noise

Regardless of what noise your tank is making, if you smell gas escaping anywhere (at the tank, along a feed line, or in your home), you should shut down the gas line and call a repair technician immediately.  If you smell gas coming from a portable unit, it’s best to close the tank and take it to a refill or swap station to have it inspected or replaced.

Make Boulden Brothers your trusted propane provider. Don’t forget that we also offer portable tank refilling at multiple locations! To keep your propane tank, HVAC, plumbing, and electrical system operating at peak efficiency, follow us on FacebookTwitter, and Google+ for more useful information and handy tips!