Open Roads Forum

Print  |  Close

Topic: Help with Propane Valve leak

Posted By: Topofhub on 04/25/09 05:52pm

Hello all,

I recently before storing my 1993 Pace Arrow had the propane tank filled. After picking it up a few weeks ago when I pulled it into the drive way I heard the tank leaking and identified where it was coming from on the tank. It stopped within a few minutes and did not come back. Last week I drove it around for about 45 minutes and then checked it again and once again there were no leaks. I did not give it much thought after that thinking that some type of o-ring must have seated in better and maybe it would not be a problem. Ok the RV has been sitting since then and today it reached 80 degrees and out of the blue the leak came back. I should mention that it is leaking on the inside not on the outside threads where it threads into the tank. I have included some links to pictures to view and if someone could be so kind as to identify this valve (such as relief or other type) I would very much appreciate some input on your thoughts in taking care of this issue. Thanks in advance.

The following pictures might help:

1. Link #1

2. Link #2

3. Link #3


Posted By: RJsfishin on 04/25/09 06:11pm

I just looked, my arangement is identical to that, except that fitting is not there. I wouldn't know what it is, but I'd bet you don't need it.


Rich

'01 31' Rexall Vision, Generac 5.5k, 1000 watt Honda, PD 9245 conv, 300 watts Solar, 400 watt inv, 2 12v batts, ammeters, led voltmeters all over the place, KingDome/sat, 2 Oly Cat heaters, and towing a Dodge GCV, or a Lowe bass boat, or a Kawi Mule.



Posted By: CloudDriver on 04/25/09 06:59pm

When in doubt, Google can find anything. Check here. It's an internal pressure relief valve. Your tank may have been overfilled. Burning off some propane with the stove or other appliance should resolve the problem.


2003 Winnebago Minnie 24F - Ford E-450



Posted By: pkunk on 04/25/09 08:47pm

That is a pressure relief valve. Usually, using some gas will solve the leaking. You could cool the tank with an ice pac especially in hot weather and an over filled tank. If the gage showes less than 80% and it continues to leak it needs to be replaced. Go to a propane service/dealer and they can evacuate the tank and replace it.


1999 Coachman Mirada 34 ft.V10-F53 chassis
12ft.LR slide-2 gp31 AGM 12V @220AH



Posted By: bassin on 04/26/09 05:42am

You should have the tank looked at . A few years ago the y had to change the valve design on tanks so you could not over fill them. Propane will exspane as it warms then it needs to vent this pressure. On the older style tanks you could open the bleeder vavle to release this pressure .


1997 Chevy 1/2 ton
1970 17' Forrester
1972 17' Chrysler skiboat


Posted By: bassin on 04/26/09 05:51am

Loooked and reread your post is it leaking out of the connection with out the cap . If so this is the return line so that they can fill your propane tank. The on marked "fill is where they put in the liquid propane . As you use propane it turns into a vapor the vapor has to have somwhere to go as they fill your tank. They use this fitting to do that. I would say that the o-ring that reals this is shot. It is like a valve stem in a tire/tube . Hope this helps alitle. Still would get it looked at just the same.


Posted By: RJsfishin on 04/26/09 06:49am

I think I have the answer.
The tank shown is for sure not OPD equipped, therefore the relief valve is not built into the shut off valve assy like mine is, which is why that valve is missing on mine. So, as was said, that is very likely the pressure relief, that is releasing propane because the tank was filled a little too full in cooler weather. And like was said, just burn off a little propane, or release a little thru the bleeder valve, and the problem will not exist.


Posted By: RVnRobin on 04/26/09 07:40am

Yeah, look at the gauge in picture 1 and 3, the tank has been over filled! I never like to waste propane, so go camping! For at least a couple days, preferably longer. Use the refrigerator, furnace, water heater, etc. The level will go down and the venting will stop.


So much to experience, so little time.



Posted By: Topofhub on 04/26/09 10:38am

Thanks to all for the response,

After reading the responses that the tank could be overfilled I looked at my gauge and sure enough it is pegged all the way. Propane GaugeI am in the process of running the fridge and cranking up some heat to remove some from the tank. It is not an easy task considering it’s a beautiful 80% New England day. Unfortunately I can’t go camping as RvRobin suggested because I have removed the right side exhaust manifold and have ordered a new one.

Thanks again and I will let everyone know how I make out.

Kevin


Posted By: red31 on 04/26/09 01:44pm

Do you watch when you tank is being filled?
Do they stop when liquid comes out the spew valve (80% valve)?
Your warning sticker suggest to have a qualified person check you tank if the automatic stop fill device does not function.
Could the leaking valve be a liquid withdrawl valve and the pressure releif valve is elsewhere?
If it is turly overfilled, open the spew valve until no liquid comes out!

Pressure relief are set for 325 psi (?)


Posted By: RJsfishin on 04/26/09 06:24pm

red31 wrote:

Do you watch when you tank is being filled?
Do they stop when liquid comes out the spew valve (80% valve)?
Your warning sticker suggest to have a qualified person check you tank if the automatic stop fill device does not function.
Could the leaking valve be a liquid withdrawl valve and the pressure releif valve is elsewhere?
If it is turly overfilled, open the spew valve until no liquid comes out!

Pressure relief are set for 325 psi (?)

For your information, his tank does not have an automatic stop fill valve, (OPD) nor is it required to have one, because it is an older permanently mounted propane cylinder. They are dependent strictly on liquid at the bleeder valve to not overfill. And I believe the older non OPD equipped tanks had 10% bleeder valves, unlike the 20% OPD valves. Thats why all the newer OPD tanks don't hold as much propane as the same size older ones. There is nothing unsafe about the older non OPD tanks, except if they are overfilled, and start bleeding off near an open flame, and even then they are designed to bleed off slowly so as to dissapate into the atmosphere, causing minimal chance of ever being ignited by anything but a very near open flame. For saftey reasons, the posted safe distance is 50 feet.


Posted By: red31 on 04/26/09 09:05pm

RJsfishin wrote:

For your information, his tank does not have an automatic stop fill valve, (OPD) nor is it required to have one, because it is an older permanently mounted propane cylinder.

It has a sticker in the pics suggesting it is equiped with an auto stop fill (required) which is now what is known as OPD. Auto stop fill in ASME tanks have been around longer than the recent OPDs used in DOT cylinders.

"The MH tank is an ASME (American Society of Mechanical Engineers) design and does not require the new OPD (Overfill Protection Device) valves because it already has a check valve and overfill protection , albeit a different design than cylinders."

propane info!


Posted By: javaseuf on 04/26/09 09:35pm

bassin wrote:

Loooked and reread your post is it leaking out of the connection with out the cap . If so this is the return line so that they can fill your propane tank. The on marked "fill is where they put in the liquid propane . As you use propane it turns into a vapor the vapor has to have somwhere to go as they fill your tank. They use this fitting to do that. I would say that the o-ring that reals this is shot. It is like a valve stem in a tire/tube . Hope this helps alitle. Still would get it looked at just the same.


Sorry but your information above is not quite accurate.

Propane tanks do not have "return lines".
The vapor in a tank can compress so it doesn't need "to have somewhere to go". As it compresses, the vapor changes back into a liquid.
In fact, many of the portable tanks of many years ago, had no purge valve to release vapor and were filled by weight. In other words, as I said above, the vapor compresses, changes back to a liquid state and doesn't need to be released from a propane tank when filling.
And BTW, when filling any MH or modern portabe propane tank, the vapor can be released into the atmosphere via the small 10% purge valve shown in the OP's picture and doesn't need to be returned to the tank.

And, it was determined and confirmed a few threads before yours (yesterday) that this is the safety pressure valve.

* This post was last edited 04/27/09 12:24am by javaseuf *






Posted By: RJsfishin on 04/26/09 09:51pm

Quote:
It has a sticker in the pics suggesting it is equiped with an auto stop fill (required) which is now what is known as OPD. Auto stop fill in ASME tanks have been around longer than the recent OPDs used in DOT cylinders.

--------------------------------------------------------
Ok, my mistake then. The OPD is identifiable by the handle on the shut off valve. I didn't know the auto stop fill existed before them. Hey, I learn something new every.....other day

Just for info tho, my 84 Itaska had a 14 gallon tank w/o the OPD, and w/o any auto stop fill of any kind. And it did not require the OPD because it was a permanent mounted "tank". It was over filled quite often, only because I was headed out, and the fridge was burning, and no chance of bleeding off. So I kinda assumed this was the same older tank w/ no auto stop.

* This post was edited 04/26/09 10:08pm by RJsfishin *


Posted By: RJsfishin on 04/26/09 10:33pm

Quote:
The vapor in a tank can compress so it doesn't need "to have somewhere to go".
-----------------------------------------------------------------------------
We know that a tank can be filled from completely empty to completely full w/o ever opening a bleeder valve anywhere,... and I do mean "completely" full !
Therefore I'm not convinced that the vapor (or air) is being compressed, or if its going back into the tank somehow. If it was being compressed, the tank could not be filled completely, and I know they can be completely filled till liquid comes out the vapor outlet valve. I have been gravity filling the 1 lb bottles for 30 years, and this has always been a mystery to me, as those bottles will fill 100% w/o any bleeding,....not to say that they don't fill faster if you do bleed them.


Posted By: javaseuf on 04/27/09 12:19am

RJsfishin wrote:

Quote:
The vapor in a tank can compress so it doesn't need "to have somewhere to go".
-----------------------------------------------------------------------------
We know that a tank can be filled from completely empty to completely full w/o ever opening a bleeder valve anywhere,... and I do mean "completely" full !
Therefore I'm not convinced that the vapor (or air) is being compressed, or if its going back into the tank somehow. If it was being compressed, the tank could not be filled completely, and I know they can be completely filled till liquid comes out the vapor outlet valve. I have been gravity filling the 1 lb bottles for 30 years, and this has always been a mystery to me, as those bottles will fill 100% w/o any bleeding,....not to say that they don't fill faster if you do bleed them.


When propane is compressed, it changes back into a liquid. This would explain what happens to the vapor inside a tank. As more liquid is introduced to the tank, the vapor compresses and reverts back to a liquid.


Posted By: RJsfishin on 04/27/09 05:48am

I'll buy that, but what about when the tank is empty and the valve is left open, leaving nothing but air inside. Any time a tank runs out of propane, and the valve or burner etc was not turned off, I have to believe it is then full of air. That air has to go somewhere, because that same tank will gravity fill right to the very top. The little ones do and so do the big ones.

This is also why I do not believe in purging a tank,...never have, and never will,... because I never had a problem. I have even built several custom shaped propane bottles,....like 3-6 lb'ers, (long skinny ones) and never a problem,.....except getting them filled when I didn't personally know the filler But I usually always gravity filled them off a larger tank.


Posted By: red31 on 04/27/09 06:52am

RJsfishin wrote:

Any time a tank runs out of propane, and the valve or burner etc was not turned off, I have to believe it is then full of air.
I don't believe this! How does this air get in there? What force(s) causes the air to go upstream into the now 'empty' pressure vessel and replace the propane vapor it is 'full' of?
Yes, some air can get in, but it is mainly propane vapor. If air is present (first fill, valve removed, etc) it will compress.
There is no excuse for overfilling a propane tank/cylinder/bottle/pressure vessel. The vapor cushion is needed to accommodate the volatile nature of propane with respect to temperature and pressure.


Posted By: javaseuf on 04/27/09 09:17am

red31 wrote:

RJsfishin wrote:

Any time a tank runs out of propane, and the valve or burner etc was not turned off, I have to believe it is then full of air.
I don't believe this! How does this air get in there? What force(s) causes the air to go upstream into the now 'empty' pressure vessel and replace the propane vapor it is 'full' of?
Yes, some air can get in, but it is mainly propane vapor. If air is present (first fill, valve removed, etc) it will compress.
There is no excuse for overfilling a propane tank/cylinder/bottle/pressure vessel. The vapor cushion is needed to accommodate the volatile nature of propane with respect to temperature and pressure.


The "vapor cushion" is mainly needed so vapor, NOT liquid propane is drawn. You introduce liquid propane into the regulator and then into an appliance orifice and you will have quite the fireworks show.


Posted By: RJsfishin on 04/27/09 10:59am

This kinda got off track a little, so really isn't about overfilling. We know that overfilling can be prevented. Filling to the top was merely an example of "where did the air go"

When a tank runs dry and is left on, it smells, because the vapor (whats left of it) continues to dissapate into the atmosphere, and as it does so, it is being replaced by air. When the tank is filled, the (mostly) air goes somewhere.

A new tank that is guaranteed full of air, fills exactly the same as an old tank, and up till OPDs, could be overfilled right to the top,....I've done it more than once. So, where did the air go ?

We once had a 300 gal tank brought out to the job. It was designed to fill our forklift tanks using gravity fill. BTW, not many know that this service is available. It could take time to fill using the bleeder valves. Then we found that if we connected the tanks before we went home, the next morning the lift tank would be chucked to the lid (overfilled) w/o any bleeding at all. We continued to do it this way for years as there was no wasted venting, and the lift tanks didn't have to be filled as often, and there was no chance of bleeding off, because the lifts were running all day.
Here again, how did the tanks get so full w/o any bleed off,.....sure don't seem like any compression could take place w/ just using gravity flow. Ever since then, I have used this same method for filling the 1 lb bottles. As they overfill, I bleed off about 10% after filling.

Its still a mystery to me how this works, probably always will be. But thru all this, some have learned that the bleeder valve isn't needed to fill a tank, except under gravity filling, it is faster to use it.


Posted By: red31 on 04/27/09 12:29pm

Propane is volatile. This means it easily changes from liquid to vapor and back with little change in pressure/temperature (Propane vapor pressure)Propane vapor pressure.
The 80% spew valve is based on 40F (per NFPA 58), fixed liquid level.
Different size tanks (large) and underground tanks can be filled to different percent full.
Once again, this vapor cushion is there so that as the tank heats up from the enviroment, the vapor compresses versus the pop off valve venting.
Several 'propane' stores in TX are still go by Butane as in Dallas Butane, they stop using butane since it is more volitile than propane.

As to gravity filling, the vapor changes phase and bubles up through the liquid column. gravity filler/drainer! (scroll down) faster filling can be done by chilling the recieving vessel and or heating (sun) the supply vessel.

Maximum Permitted Filling Density: The maximum liquid level to which a propane container should be filled, as to allow for vapor expansion in the container. This permitted filling level is determined by ambient temperature and the temperature of the propane.

* This post was edited 04/27/09 12:46pm by red31 *


Print  |  Close