Did overfill protection worked? (5.9 gallons)

[RT1997]

My new Manchester propane tank has the same 5 gallon capacity as my old one on RT 170 .And it is supposed to be only 80% filled. So if overfill protection works the shut off should be at 4 gallons or slightly over.
I am not sure how well that protection worked on the old tank but definitely at 5 gallon mark at the filling station
the RT tank "refused" to take any more and the rest were coming out until the tech turned off their machine.
I usually monitored the process and asked to stop according to the gauge readings.
I recenly went to a propane place with new Ferrell Gas high tech filling machine that supposedly stopps itself when necessary.I don't know the details,that was what a tech told me a while ago.
Anyway,I was counting on my tank overfill protection.
So the process went seemingly fine.The machine stopped.No hissing propane in the process of detaching the nozzle.But it stopped at 5.9 (!) gallons.And the gauge on my tank pointed far over "full" mark.
I know that Manchester tank can hold more than 5 gallons.
But there is the gauge and 80% requirements.
Of course from now on I 'll myself become the gauge )): and monitor the process.Even if the overfill protection is faulty shipping the tank back to Canada ($$) and paying another $$$ for installation ( even if it might be less than 5 hours second time) is insane .But would be interesting to know your opinion on how did that happen - did Farrell Gas high tech machine "overide" RT tank signal ?
Again- weather or not the machine is really high tech I only heard from the propane station employee.

Side question - any possible damage from one time overfill?

[RT-NY]

I think that you tank holds more than 5 gallons. You should check on the information plate on the tank, but, according to the roadtrek brochure for your model year, it is supposed to be a 30 pound tank, which holds seven gallons. In the later model years it gets a bit bigger, a 35 pound tank that holds eight gallons.

Regarding the 80 percent calculation -- I had thought that the listed weight of the tank is how much propane it can hold so it already takes off the 20 percent. So a 20lb portable barbecue tank holds about 4.7 gallons of propane (which weighs something like 4.24 lbs per gallon), and your 30 lb tank holds a bit more than 7 lbs. But forum members - please correct me if I am mistaken on this.

[RT1997]

Thank you for the information.
The other question is - should the gauge mark "Full" determin where to stop or the gauge is there just to have an idea how much propane left ?

[booster]

Originally Posted by RT1997

Thank you for the information.
The other question is - should the gauge mark "Full" determin where to stop or the gauge is there just to have an idea how much propane left ?

The gauges are notoriously inaccurate from all that everyone has told me, including the propane experts.


The spit valve is the best way to determine full unless the OPD shuts it off first, like ours does.

[RT-NY]

Originally Posted by booster

The gauges are notoriously inaccurate from all that everyone has told me, including the propane experts.


The spit valve is the best way to determine full unless the OPD shuts it off first, like ours does.

Booster -- can you explain how to use the spit valve correctly? I think that some liquid come out of mine even before it is completely full, though I am not sure.

[booster]

Originally Posted by RT-NY

Booster -- can you explain how to use the spit valve correctly? I think that some liquid come out of mine even before it is completely full, though I am not sure.

Ours will look like liquid coming out a bit because the gas condenses on the cool fitting but it is mostly vapor. It has never gotten to full liquid out of it point because the OPD stops it. Propane people tell me that when liquid comes out you get a bit of stream and lots of vapor as it evaporates.

[RT1997]

Originally Posted by booster

The gauges are notoriously inaccurate from all that everyone has told me, including the propane experts.


The spit valve is the best way to determine full unless the OPD shuts it off first, like ours does.

So if propane starts coming out through the nozzle is normal indication that the tank is full 80% ?

And does it also indicates that overfill protection not working ?

P.S. The vapor fumes from old tank sometimes were very strong and it was hard for a tech to detach the niozzle - the vapor kept coming like crazy.

[RT-NY]

OK - well, I am not completely sure about the spit valve, but I think that the idea is that you open it a little bit while filling and it will hiss but no liquid will come out. As the tank starts to get full the hissing will be accompanied by a kind of spitting of liquid. At that point you stop filling.

This makes sense in theory, but my experience with propane filling places is that they won't use it. Hissing propane sounds dangerous to them and they will not abide it.

[RT-NY]

Originally Posted by RT1997

So if propane starts coming out through the nozzle is normal indication that the tank is full 80% ?

And does it also indicates that overfill protection not working ?

Yes, I think so: if *liquid* propane is coming out of the spit valve (the small valve near the fill valve), then yes, it is 80%. But, I am not sure that means the OPD (overfill protection device) is not working, because I think that it depends on how that device is installed and adjusted.

[RT1997]

Thank you, RT-NY.All of these facts are steering me in the direction of human monitoring and trying to get 4 gallons total.With unreliable gauge it is still only approximate.But I don't like the vapor streaming out.It might be damaging if happens often.

[RT-NY]

Originally Posted by RT1997

Thank you, RT-NY.All of this facts are steering me in the direction of human monitoring and trying to get 4 gallons total.

But I still don't know why you are thnking only 4 gallons. This is very little - it is less than a portable BBQ container takes. I think that your tank takes much more than that. It will say on the plate on the tank - you posted a picture of it previously, though I could not read it from that.

[RT1997]

I am relying on the original manual of my RT that mentions 5 gallon capacity. It is not clear wheather it already includes 80% of the bigger tank .If not -4 gallons is 80% from 5.
I do underatand that the tank itself can hold more But 5 gallons - in the manual.
I will ask Canadians later ( they are closed till Jan.8 for holidays).

P.S.I can not check the manual now.But believe that it says 5 gallons.And in my previous experience when a tech filled over 5 gallons ( one time it was 5.6) it was always a vicious vapor hissing.

About what says on the plate - it was almost impossible to read in person. The indented text wss carved in and painted over. Of course it is even worse in the picture which I tried to edit.

[booster]

Originally Posted by RT1997

I am relying on the original manual of my RT that mentions 5 gallon capacity. It is not clear wheather it already includes 80% of the bigger tank .If not -4 gallons is 80% from 5.
I do underatand that the tank itself can hold more But 5 gallons - in the manual.
I will ask Canadians later ( they are closed till Jan.8 for holidays).

I think all tanks are marked with their capacity and probably all have total amount and a fill amount. Do you not have that?


Roadtrek specs are known to be wrong in many cases, on many specs.

[RT1997]

Booster,my repliy came before your post I could not read what was on the tank.Will call Canadians later.
And yes - RT manuals are not much model specific (like many others).

PS. Since the new tank fit perfectly in the old tray -
I am assuming the capacity is the same.
And the old tank was "spitting out" all lp over 5 gallons most of the time.

[RT-NY]

Originally Posted by RT1997

The vapor fumes from old tank sometimes were very strong and it was hard for a tech to detach the niozzle - the vapor kept coming like crazy.

Originally Posted by RT1997

And the old tank was "spitting out" all lp over 5 gallons most of the time.

I just want to make sure that we are not talking about two different things -- the "spit valve" is a separate small valve to the left of the fill valve (in your picture). When you say that "vapor kept coming out" and "the old tank was spitting out" it sounds like you mean that propane was coming out of the *fill valve* from around the hose connection. I do not think that propane is supposed to come out of the fill valve at all apart from when the hose is being unscrewed. It sounds like you are saying that more propane comes out when unscrewing or it becomes more difficult to unscrew the more full the tank is. This is not the case for my tank because it has a check valve on the fill port and a remote fill, but yours might be different. But in any case, it has nothing to do with 80 percent full specifically. The small spit valve, on the other hand, is designed to spit liquid at 80 percent full.

And regarding the overfill prevention that you asked about from the start: that will only kick in when it reaches 80 percent full according to the manufacturer's tank specfications, not other recommendations that you read elsewhere.

[RT1997]

Yes, propane fumes were coming out of the fill valve making it difficult to detach the nozzle. It happened mostly when it was more than 5 gallons.That was when I had the old tank.
That's why I was surprised and concerned about 5.9 gallons on exactly the same size new tank.
I hope to get some clarification from MobilifeRV .They have a very experienced tech in service dep.
I simply want to make sure that no damage was done.
It was a very stressful experience of replacing the tank.

[Ken Allan]

We have a Manchester 5.9 gal tank. It can only be filled to 80% (safety limit) because there is a mechanical fill valve inside that stops any more propane liquid from going in. At 80% the dial gauge will show about 3/4 full because, well, the tank is about 3/4 full.

For ref: 80% of a 5.9 gal tank is 4.7 gal which equals 20 lbs of propane.

I have found when my tank dial reads "zero" there is still about 1.3 gal of propane left in tank. What?? What's going on? Inside the tank there is a mechanical float that turns a shaft that has a small magnet on the end. This magnet moves the outside dial. The problem is... If you track down the actual inside tank gauge float mechanism you will find it it is designed to be used on a 10 to 22" diameter tank.

We have an 8" diameter tank. The manufacturer, (Rochester Gauges) states it will not be accurate on other size tanks. Apparently something about the float geometry will allow the dial to read zero when in fact there is still propane left in tank.

I would very much prefer that the gauge dial was accurate when tank is near empty. Who cares that it does not read correct at full? This dial gauge is NOT used to fill our tanks. ---KenA


ps... US gallons. Tank is 8" dia x 30" long.

Manchester ASME LPG Tank, model #68265, 5.9 gallon

[RT-NY]

Originally Posted by RT1997

Yes, propane fumes were coming out of the fill valve making it difficult to detach the nozzle. It happened mostly when it was more than 5 gallons.That was when I had the old tank.
That's why I was surprised and concerned about 5.9 gallons on exactly the same size new tank.
I hope to get some clarification from MobilifeRV .They have a very experienced tech in service dep.
I simply want to make sure that no damage was done.
It was a very stressful experience of replacing the tank.

OK. Well, as far as I know propane fumes should not come out of the fill valve at all when filling so I do not know why they were with your old tank, but I do not think that it was because the tank could only hold 5 gallons. And I think that it is not likely that any damage was done to your new tank by putting in 5.9 gallons. But I agree that it would be a good idea to check the capacity specification with MobileRV -- it should be very easy for them to check.

[RT1997]

Originally Posted by Ken Allan

We have a Manchester 5.9 gal tank. It can only be filled to 80% (safety limit) because there is a mechanical fill valve inside that stops any more propane liquid from going in. At 80% the dial gauge will show about 3/4 full because, well, the tank is about 3/4 full.

For ref: 80% of a 5.9 gal tank is 4.7 gal which equals 20 lbs of propane.

I have found when my tank dial reads "zero" there is still about 1.3 gal of propane left in tank. What?? What's going on? Inside the tank there is a mechanical float that turns a shaft that has a small magnet on the end. This magnet moves the outside dial. The problem is... If you track down the actual inside tank gauge float mechanism you will find it it is designed to be used on a 10 to 22" diameter tank.

We have an 8" diameter tank. The manufacturer, (Rochester Gauges) states it will not be accurate on other size tanks. Apparently something about the float geometry will allow the dial to read zero when in fact there is still propane left in tank.


ps... US gallons. Tank is 8" dia x 30" long.

Manchester ASME LPG Tank, model #68265, 5.9 gallon

Thank you very much for this valuable information.
But how you can be sure that the mechnical valve that insures 80% is not malfunctioning or broken?
"You can not overfill" - if it is true -that 's great news!

[jojobafanzi]

Originally Posted by RT1997

Thank you very much for this valuable information.
But how you can be sure that the mechnical valve that insures 80% is not malfunctioning or broken?
"You can not overfill" - if it is true -that 's great news!

Let this allow you some comfort. You did not do any damage to your tank by over filling it. The 80% full requirement is because the tank tapers at the top due to its shape and propane vaporizes from the surface. If you over fill the tank right to the top, the propane may not vaporize fast enough to feed a full load on the LP system. You would get a low pressure situation until enough propane was used to allow enough surface area of the fuel to supply the demand. Keep in mind, that full load means all appliances working on full all at the same time. The OPD is a float attached to the fill valve and they can get stuck. I will send a picture of one later when I visit my shop. I own a gas company. The fuel gauges often get stuck and are often not accurate. The bleed valve is nothing more than a straw into the tank that allows fuel, either vapor or liquid to exit at a controlled amount while filling. Vapor exits this manually opened valve while filling until the fuel level reaches the straw and liquid spurts out. The liquid quickly vaporizes at atmospheric pressure but not before you can visually see it. This valve is always used on home fuel tanks but can be dangerous on RV's so some filling station techs don't like to use it. If there is an ignition source or static electricity present, it can ignite the bleeding vapor during filling. Also, LP vapor may enter the RV through a vent or open door. This is why I always turn on my electrical house system during filling my RV and ensure all pilot lights such as refrigerator are extinguished. I keep power on so the LP detector is activated. I also keep away from the filling tech and stand next to the filling stations emergency shutoff switch with my CO2 fire extinguisher in hand. There is always a risk of fire but following procedure keeps the risk low and being ready can keep a flash burn on your arms from turning into a totally destroyed RV. Always be sure that people and pets are not in the RV while the tank is being filled.
Cheers! Joe