Even though propane suppliers leave space in propane tanks for the liquid to expand (the typical is 80%), sometimes it’s filled excessively because of reasons such as faulty filling equipment or inexperienced personnel.
Now, if you suspect your propane is overfull, it’s very important not to use it until after fixing the overfill- when propane expands, an overfull tank poses hazards such as leaks or worse yet, explosions.
In other words, lighting up an overflowing propane tank is playing with fire, literary!
That is the bad news..
The good news is bleeding a bursting propane tank is fairly easy and it’s a task you can do at home.
Read on to learn how to bleed an overfilled propane tank if you feel your tank was filled over the recommended 80%.
How to bleed an overfilled propane tank
Here is how to bleed a propane tank:
Before proceeding, ensure you’re in open air and that there are no flames or sparks anywhere near- You don’t want to start a fire!
- Open the bleeder valve to allow propane to squirt out of the tank.
- Let the excess continue escaping out – you’ll note its actual liquid propane spouting from the bleeder- until the liquid level dips to about 80%. When it reaches this point, bursts of vapor (traces of the liquid may be intermixed) will start to come out.
- Once you notice mist starting to be expelled to the atmosphere slowly, shut the bleed valve.
Voila! Your tank is now likely safe to use.
Side-Note: In most of the cases, the bleeding process takes anything between a few minutes (if the tank was just slightly overfull) to 1-2 hours to complete (for extreme scenarios).
How to purge a propane tank
A practice that helps in preventing problems filling is purging your new tank.
Not only will the tank fill faster after purging but it also functions more reliably all the time.
For starters, purging is simply expelling the pressurized air that new tanks ship with so that it can be filled without issues (when purging, the tank is filled with a bit of propane and then emptied).
To purge your tank:
- Hook up a full previously purged propane tank to the new tank – the connection should be made using a purge kit or a connecting line having a regulator, a bleed port, and a two-way valve.
- Set your purge valve to ‘purge’.
- On the new tank, open the valve typically by turning it counterclockwise.
- Now set your connecting line’s valve to ‘charge’. This allows propane into your new tank. Wait for propane to stop flowing (you should not wait for more than a few minutes).
- On the old tank, set your connecting line valve to ‘purge’. Propane vapor now bleeds out of the new tank (lasts about 1 minute).
- Repeat steps 2 to 5 about three to four additional times.
That’s it. Your tank is now ready for safe filling.
Signs your propane tank is overfilled
Oftentimes, it’s not easy to be completely sure that your household or barbecue tank has been overfilled.
So, how do you tell if your tank is too full after coming from the local outlet where you usually get it filled?
Answer: Watch for these telltale signs:
- Propane oozing out of tank- in some cases, you may notice a stream of propane coming out of the tank immediately the attendant disconnects his equipment. Normally, there should be nothing or just a momentary spurt.
- Propane odor around the place- if you can smell Ethyl Mercatan or Ethanethiol (the chemical that gives propane gas its odor), then you probably have a leak or an overfull tank. Check if there are any obvious leaks and if you find none, take it as a possible overfill (more on testing for overfill next).
- No fuel– there is also a chance your appliances- furnace, grill, etc.- will not receive any fuel meaning they won’t work.
Testing if a propane tank is overfilled
To be double sure, you can actually test the tank for the possibility of having been overfilled.
Conducting the test is pretty simple as long as your tank has a functional bleeder valve.
All you have to do is open the bleeder valve very slowly then shut it off immediately.
Near-liquid propane spews out in a solid stream if your tank was filled over the safe 80% and you should proceed to bleed it as outlined.
On the other hand, there is no cause for alarm if the tank emits just a mist (mostly vapor) of propane. As mentioned, emission of vapor signals that a tank is optimally filled.
How to bleed an overfilled propane tank – (FAQs)
Is it safe to use an overfilled propane tank?
Since there’s no room for the liquid to expand into, your overfilled propane tank could suddenly explode, causing massive damage and horrible injuries.
The other scenario is the tank forcing the relief valve open, spilling propane- That is not a good thing either as it would amount to wasted money.
With that in mind, try to bleed the excess off your tank before use especially if it’s an extra hot day- having the tank over 80% is mostly dangerous in very hot temperature since propane expands when the ambient temperature rises.
How do I empty my small propane tank?
Here is how to empty a small propane tank for safe transport to a refill station, storage, etc:
1. Disconnect everything from the propane tank and take the tank to a safe spot outdoors.
2. Change the position of the tank to have the valve point sideways.
3. Now open the valve. Propane will begin to flow out.
4. Wait until no more propane is coming out- it empties fully in just a few minutes.
5. Close the valve.
After bleeding the tank, take steps to have an OPD (Overfill Prevention Device) installed in your tank (if your tank is one of the older models that come without).
If your tank has one but you suspect it’s faulty, have it repaired by a professional.
This will prevent the problem from occurring again at a later date.
In addition, always refill your tank at a reputable propane dealer.
You can even go as far as watching the attendant as they perform the task – of course, human beings tend to be keener on their jobs when being supervised!