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Topic: LPG Gas And Cold Weather (Read 4 times) previous topic - next topic
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LPG Gas And Cold Weather
Yahoo Message Number: 19001
There are two threads on the site that report malfunctioning LPG gas appliances when the outside temperatures were very low.  A comment made by Steve (Aq433) questioning whether the fuel was rated for the low temperature brought to mind the comments by Al Coho at Life On Wheels.  Al lectured on LPG and LPG appliances when we were at the conference in Moscow, ID last July.
 Al said that two different liquified gases are supplied as "propane".
One is propane and the other is butane.  At atmospheric pressure, propane boils at -44 degrees F while butane boils at +32 degrees F.
In other words if it is below freezing, there will be little or no pressure in a tank of pure butane but still fairly good pressure in a tank of pure propane.  If there is no pressure, your LPG appliances will not work.  He mentioned the "problem in the middle of the night" symptom that often points to an LPG source problem.

Al continued that either gas burns equally well and the flames are similar so you cannot readily tell them apart without complicated testing.  Butane is apparently often sold either pure or mixed with some propane in the warm climate states especially during the summer.
Relativly pure propane is provided in the winter months in cold climate states.

Al said there were a couple of things that you should keep in mind with LPG.  Avoid filling the tank completly full where it was cold and then driving into a warm climate.  This might cause the liquid in the tank to expand and fill the part of the tank reserved for vapor.
This will cause the tank's relief valve to vent liquid LPG to relieve the pressure. This will create a momentary but very dangerous fire hazard. Since last April all LPG tanks must have an automatic fill valve which is designed to prevent over filling the tanks. This makes this problem much less of a concern than it used to be but Al is very conservative where safety is concerned so he told us about it anyway.
 Second, he counciled that if you are going from a warm climate into a cold one, leave the LPG tank mostly empty and fill it when you get to the cold climate.  That way you will get LPG that is mostly propane that works well at cold temperatures.  It works fine if you carry propane from a cold to a warm climate.

So, if you have suddenly experienced a problem with your LPG appliance after it got very cold outside, try filling your tank locally to dilute the LPG you have with something more suitable for your climate.  Do not attempt to vent the LPG already in the tank.
That is extaordinarily dangerous.

Linley
Re: LPG Gas And Cold Weather
Reply #1 –
Yahoo Message Number: 19031
Quote
There are two threads on the site that report malfunctioning LPG gas appliances when the outside temperatures were very low.  A comment made by Steve (Aq433) questioning whether the fuel was rated for the low temperature brought to mind the comments by Al Coho at Life On Wheels.  Al lectured on LPG and LPG appliances when we were at the
Actually, I was not referring to the fuel. When a new LP tank is first brought into service, it will contain air - which has moisture and oxygen. It is a requirement that at the first fill it be purged.
The usual procedure is to fill it with propane GAS, then vent to atmosphere. This is repeated several times until all the air is presumed evacuated. Another better procedure uses a vacuum pump to do the evacuation, then refill with propane - no venting required beyond the evacuation. But, if neither is done, or is done poorly, moisture will remain. Under the right conditions, the moisture will freeze and plug the tank outlet.

Steve
2004 FL
2013 Honda Fit
Re: LPG Gas And Cold Weather
Reply #2 –
Yahoo Message Number: 19056
This topic of propane/butane has been written about in a few RV publications recently and in one I remember them saying that butane is typically mixed with propane even in areas of the country that have cold winters during the summer months because it is cheaper to produce. In cold weather climates they stop mixing it in as fall arrives and don't start again until spring to avoid the problems mentioned. In areas that are typically warm year round they may have some butane mixed in the propane all year long and during the summer it could be 100% butane. This all depends on the gas company supplying the propane (Amerigas, Suburban, Teco, etc) and the dealers typically have no way of knowing what they have in their storage tanks.
 These articles recommend people from the south not fill their propane tanks before getting to a colder climate if they plan to camp in cold weather to avoid the problems it can cause. They also recommend that people in northern areas not fill their tanks toward the end of summer if they won't be using most of it before cold weather arrives especially when they plan to camp in the colder weather.

Mike