Propane to butane ratio in the US?

[MoonShadow_1911]

Based on research and what folks above said, I have mine set to 100% propane.

Rob

That's what I set mine to. I didn't do the research like you have, though.

[bill8t1vette]

There is no butane in propane
Butane is usually Used in gasoline to boost the octane in it.
I haul propane for a living.

[Barry Mounce]

I would love to know how accurate it is set at 100% propane. I would guess as you increase the amount of butane on the app it would read lower volume but that is just a guess based on C3H8 propane and C4H10 butane having a slightly larger molecule causing it to be denser. Propane density as compared to water is .493 and butane .573 Please post what you find when you adjust it

QUOTE=Second Chance;462832]Since this cuts across appliances and HVAC, I thought I'd post the question in the General Tech Topics area...

The updated app for my Mopeka tank sensors has settings for the size and orientation of the tanks (in my case, 30 lb. vertical) and now ratio of propane to butane. In the past, the sensors have registers a bit more liquid in the tanks than was actually there and the lack of this adjustment may explain that. However, in using Mr. Google I cannot find an answer to what the most common ratio is in LP sold in the US. Does it vary by latitude? Is it fairly constant? Anyone have any idea(s)?

Thanks!

Rob[/QUOTE]

[Second Chance]

I would love to know how accurate it is set at 100% propane. I would guess as you increase the amount of butane on the app it would read lower volume but that is just a guess based on C3H8 propane and C4H10 butane having a slightly larger molecule causing it to be denser. Propane density as compared to water is .493 and butane .573 Please post what you find when you adjust it

QUOTE=Second Chance;462832]Since this cuts across appliances and HVAC, I thought I'd post the question in the General Tech Topics area...

The updated app for my Mopeka tank sensors has settings for the size and orientation of the tanks (in my case, 30 lb. vertical) and now ratio of propane to butane. In the past, the sensors have registers a bit more liquid in the tanks than was actually there and the lack of this adjustment may explain that. However, in using Mr. Google I cannot find an answer to what the most common ratio is in LP sold in the US. Does it vary by latitude? Is it fairly constant? Anyone have any idea(s)?

Thanks!

Rob

[/QUOTE]

With the sensors set at 100% propane, they read 100% when the tanks are full. The tank that emptied the other day (the regulator switched over) was still reading about 3%. That's probably about right since we never get 100% of what's in the tank out, anyway.

Rob

[MoonShadow_1911]

With the sensors set at 100% propane, they read 100% when the tanks are full. The tank that emptied the other day (the regulator switched over) was still reading about 3%. That's probably about right since we never get 100% of what's in the tank out, anyway.

Rob[/QUOTE]That's my experience as well, with mine confirm for 100% propane.

[RickLight]

How about an experiment? My tanks are full and in storage so I can't try this any time soon.

Once a tank is "empty" and reading whatever minimal level. Disconnect it, vent, and see if the reading changes.

[Laurie 1799]

How about an experiment? My tanks are full and in storage so I can't try this any time soon.

Once a tank is "empty" and reading whatever minimal level. Disconnect it, vent, and see if the reading changes.

You do not want to vent a tank to completely empty, it would then have to be purged before it was re filled.

[Tom Traveler]

You do not want to vent a tank to completely empty, it would then have to be purged before it was re filled.

The only time a propane tank needs to be purged is if it had anything other than propane in it, the most common case being a new, never filled, tank that has air in it. Propane tanks are vented empty in barbecues or your RV all of the time. “Empty” means that all of the liquid propane in the tank has vaporized and the tank has vented to atmospheric pressure. It does not need to be purged before being refilled unless for some reason you pumped air or some other gas into it under pressure.

[Laurie 1799]

The only time a propane tank needs to be purged is if it had anything other than propane in it, the most common case being a new, never filled, tank that has air in it. Propane tanks are vented empty in barbecues or your RV all of the time. “Empty” means that all of the liquid propane in the tank has vaporized and the tank has vented to atmospheric pressure. It does not need to be purged before being refilled unless for some reason you pumped air or some other gas into it under pressure.

I assumed he was leaving the 80% screw open in order to vent his tank.This would introduce air into the tank , necessitating a purge.

[Tom Traveler]

I assumed he was leaving the 80% screw open in order to vent his tank.This would introduce air into the tank , necessitating a purge.

I wouldn’t think so. If you open the screw vent, the remaining propane vapor will vent until the tank pressure equals outside air pressure. No air would go into the tank unless the outside air pressure ever becomes greater than the tank pressure. This could only happen if you leave the screw vent open for an extended time (days) and allow changing barometric pressure and changing temperature, up and down, to put a bit of air in the tank. If you close the vent shortly after relieving all of the propane pressure, no air will go into the tank and no purging needed.