Propane Tank Issues

[Wsm239]

Hello. 2008 Thor Hurricane 34B.

Our daughter has been living in it since the end of June while awaiting getting her own place. Had to fill the propane tank recently and within a day or two it was completely empty.

Looked underneath I found a female threaded receptacle which obviously something fell out or was removed since the brass threads are “like new”.

What exactly is this? A low point drain? Could this why the tank drained so quickly?

[Dutch_12078]

Wsm239 wrote:

Dutch_12078 wrote:
After seeing the sample photo, as Doug said, it's the Safety Relief Valve. Below is a picture of what one typically looks like before it has tripped.

Thanks, this is very helpful. Mine does not have the red insert that is shown on yours.

It is possible the tank was overfilled. But would it empty completely if that was the case? Or would it just empty just enough to bring it to "normal"?

Doug might have the answer to that. I haven't experienced one tripping yet. It shouldn't be possible to overfill the tank if everything is working right, but I suppose it's possible the overfill prevention device valve has failed open. A properly trained refiller should be using the Fixed Liquid Level Gauge, sometimes referred as the "vent" or "spitter valve", to determine when the tank is filled to the proper 80% of the rated water capacity regardless of whether the OPD works or not.

[Wsm239]

Dutch_12078 wrote:
After seeing the sample photo, as Doug said, it's the Safety Relief Valve. Below is a picture of what one typically looks like before it has tripped.

Thanks, this is very helpful. Mine does not have the red insert that is shown on yours.

It is possible the tank was overfilled. But would it empty completely if that was the case? Or would it just empty just enough to bring it to "normal"?

[Wsm239]

dougrainer wrote:
DO NOT fill the tank Completely, until you find the leak. Just pump a gallon or 2. Then use soapy water around ALL the fittings on the tank. The tank should have more than enough clearance to cawl under it to soak the bottom fittings. That bottom fitting is usually the tank valve relief. It SHOULD reset after it trips, but it may now be faulty. I would replace it if that is where the soapy water bubbles. If you only put a gallon or so in the tank, then bleeding it off by emptying the tank will not take long. The tank has to be empty of liquid and vapor to replace that valve. I would highly advise you to have a LP company replace the valve after you verify the problem. Doug

Thanks, I did try the soapy water spray but no bubbles anywhere. I will for sure be hiring a licensed propane person to make any changes or repairs.

[Dutch_12078]

After seeing the sample photo, as Doug said, it's the Safety Relief Valve. Below is a picture of what one typically looks like before it has tripped.

[dougrainer]

DO NOT fill the tank Completely, until you find the leak. Just pump a gallon or 2. Then use soapy water around ALL the fittings on the tank. The tank should have more than enough clearance to cawl under it to soak the bottom fittings. That bottom fitting is usually the tank valve relief. It SHOULD reset after it trips, but it may now be faulty. I would replace it if that is where the soapy water bubbles. If you only put a gallon or so in the tank, then bleeding it off by emptying the tank will not take long. The tank has to be empty of liquid and vapor to replace that valve. I would highly advise you to have a LP company replace the valve after you verify the problem. Doug

[Wsm239]

https://applianceanalysts.com/rv-propane-tank-size/

Having difficulty posting a picture. This link shows the port I am referring to on the bottom of a built in tank.

[Wsm239]

Alan_Hepburn wrote:

opnspaces wrote:

But realistically you should be able to fill the tank, turn it on it's side, lean over and put your nose against the hole and take a sniff. If it's leaking you will know.

Realistically, it's a bit of a project to turn the tank on it's side - it's installed pretty sturdily under the Class A motorhome...

Agreed, I am not going to even try to flip it on its side!!! LOL!!!

[Alan_Hepburn]

opnspaces wrote:

But realistically you should be able to fill the tank, turn it on it's side, lean over and put your nose against the hole and take a sniff. If it's leaking you will know.

Realistically, it's a bit of a project to turn the tank on it's side - it's installed pretty sturdily under the Class A motorhome...

[opnspaces]

Fill the tank then take a piece of masking or painters tape and place it over the port. Spray or even dribble soapy water around the tape and see if you get bubbles. The tape is to narrow the opening that the gas is escaping from to help it bubble.

But realistically you should be able to fill the tank, turn it on it's side, lean over and put your nose against the hole and take a sniff. If it's leaking you will know.

[Wsm239]

Thanks for the responses so far. This female threaded part I am referring to is on the underside of the propane tank itself and is recessed into the tank. Not a location that would be easily accessible for a temporary or permanent attachment of any sort of bbq or the likes.

I am unable to upload a picture for some reason.

[wa8yxm]

Photo please
I will add the Fill port is kind of large... it is outside thread (The fill nozzle fits OVER it) I'm not sure why you'd call it female save the hole in the middle... There is a check valve behind it.

There is a three 'Fingered" knob valve beside it (The Visual Overfill Indicator Valve" if the fill tech did not fully tighten that will leak you will Smell Propane if that happens. (You may for a bit even if the valve is properly closed as some propane is vented during filling)

THe other fittings on the tank are smaller

IF you have a gauge on the tank the Fill port is, as I recall Larger. (The other ports smaller).

[Dutch_12078]

If it's at the bottom, it might be a liquid withdrawal port, sometimes used for LP generators.

[dougrainer]

That female threaded fitting is the hI PRESSURE fill nozzle. The Threads look new(clean) because this fitting usually has a yellow cap installed. You remove the cap to install the fill nozzle. Since NO yellow cap, then it has been lost. Obvious cause of no LP after fill is the filler did NOT fill the tank full. If it leaked out the usual 15 to 25 gallons of LP in a few days you would hear it and smell it. You need to get a cap to cover the fill nozzle. This link shows what it is. Doug

https://www.amazon.com/Marshall-Excelsior-ME109-Tank-Valve/dp/B007HRKQ2Q/ref=asc_df_B007HRKQ2Q/?tag=...

[opnspaces]

could it have been a stub for a propane bbq and somebody stole?