Propane tank moisture

[garyre]

I believe to have moisture in my propane tank lines...my hot water heater an heater now work intermittently...Has anyone experienced this sort of problem and any recommendations to clear?
Thanks in advance for any suggestions.

[Switchflicke]

I can't imagine moisture in the lines. Air maybe. I look forward to the replies on how to remedy the problem.


Stan

[TinMan Trvlr]

When we looked at the fuel guage for our on board propane tank when we were picking up our new 2014 Dutch Star, we noticed that the needle was well above the "full" mark. Months later we made our first uses of the propane system, and the regulators on our portable propane stove and BBQ quickly seemed to let less and less propane through to the burners. When we disconnected the hoses we found there was an oily amber liquid substance dripping from the regulators. We disconnected the main regulator at the on board tank, and found the same liquid dripping from that. We called Newmar to ask about it numerous times, but no got useful reply. We told them we had a bad batch of propane, and they said no way that could happen. When we pressed them about it, they said that they ship new units without propane in the tank, that it was the dealers responsibility to put the first fill in the on board propane tank. take it up with the selling dealer.The selling dealer said they had never had a problem before, so it couldn't be something they did. They said there was no way there could be liquid in the propane tank.

After doing a ton of research and checking many other forums, we found that there were instances of this same problem happening on propane systems used by other motor coach owners and yacht sailors when their tanks had been filled beyond the 80% full mark. We also talked to some experienced propane dealer owners who added their input. Apparently the oily substance is the "carrier" for the odourant that is put into propane that makes the propane smell so it is easier to detect if there is a propane leak. When the tank is overfilled, the oily substance can get carried up through the tube in the propane tank and migrate out into your regulators and piping. If you get a lot of it into a regulator it will clog it up and stop the propane flow. It is particularly problematic when it gets into the piping for your propane fridge, since the small pilot light supply and small amount of burner consumption is so easily blocked. We were told that on higher volume propane appliances with larger regulators than our small portable stove and BBQ the oil just passes through the regulator and lays in the larger piping until it is eventually absorbed in the larger flow of propane, carried up to the on board stove and burned off. Once the level of propane in the main tank drops below the level of the pick up tube, the oily substance is no longer picked up as the propane flows out of the tank, and the problem is solved.

We found that to be the case. After we allowed the oily substance to drain from our regulators several times, then used our kitchen propane stove enough to lower the level of propane in our on board tank to below 80% the issue seemed to go away. We use a 25 foot hose off our Extend-A-Stay fitting to provide propane to our portable stove and BBQ, and the oily/waxy substance really collected in that hose. After I blew a quantity of the substance out of the long hose our small appliances worked well again too.

I enclose a photo of the wax and oil that were discharged from the extension hose the first time I allowed it to blow off. Once I realized the risk of fire from purging the hose this way I worked out a way to blow it out using compressed air. So far we have not had a repeat of the issue.

I hope this helps you track down and cure the "liquid in your lines" problem. Let us know what you find that explains and/or cures your issue.



Best wishes

[Old-Biscuit]

Got stove top burners?

Light off all of them on high and let them burn........do they sputter/spit OR burn clean blue steady flames.


Real hard to get 'water moisture' in propane system UNLESS something on propane tank was removed allowing air inside tank. If that happened tank should have been 'purged' otherwise air/propane mixture causes havoc

Air/moisture etc just doesn't get into propane system....it's pressurized

[azpete]

we had a coach come to our repair center with the same problem. the lines were full of this greasy substance. foul smelling, sticky grease. we disconnected a few points along the supply lines, pulled a swab thru the lines, and replaced the regulator.
we drained the tank and flushed it out with a gallon of alcohol. after reassembling the system and doing a leak test. everything worked. took about 4 hours total.
not hard to do, but ,what a stink.
i believe this comes from lp dealers who do infrequent sales. just like diesel, i look for a dealer with a lot of volume.

[PSOUZA]

Originally Posted by TinMan Trvlr

I hope this helps you track down and cure the "liquid in your lines" problem. Let us know what you find that explains and/or cures your issue.



Best wishes

I and several others, working independently, about two years ago, found the cause and solution to this problem.

The oil comes from the refinery distribution process where some refineries and distributors use shared pipelines. Light weight oils and propane are shipped with devices called Pigs that separate the two fluids that move down the pipes. Contamination of both products is assured, but the propane, being a solvent, dissolves and retains the oil. The propane in the oil boils off when the oils reach atmospheric pressure.

The main thing to understand from this is: Oil contamination in propane must be considered as normal, and must be planned for even though it is not universally present throughout the country.

A device popularly called a drip leg must be installed at the lowest physical point in the low pressure gas line and provision for draining that device must be installed. Regular maintenance, consisting of draining the accumulated liquid is required.

This procedure has been %100 effective when properly implemented.

The problem of contamination at individual distributors is non existent because of the nature of the storage tanks and the the pump process.


The odorant is Mercaptan and is a gas, not an oil. There is no carrier to deliver Mercaptan in propane. A carrier is needed to carry Mercaptan in Liquefied Natural Gas and propane is used for that purpose.

Phil

[TinMan Trvlr]

Thanks for that input PSousa. Despite what I was reading, I could not believe that there would be as much oil added to a fill of propane to carry the Mercaptan odourant as we were finding in our regulators and piping. Adding a drip leg to the low point of our coaches propane piping that can be drained periodically is a simple worthwhile solution.

We have already added a "Mr.Heater" filter to our Extend-A-Stay 25 foot propane line that serves our patio side use of the portable cook stove and BBQ, and occasionally remove and drain any built up oil that collects in it.

Is there anything short of the 4 hour clean out process posted earlier in this thread that can be done to eliminate the oil that may have dropped out of the propane in our main on board tank, and may be added to again by carry over oil included in the next propane fill? Clearing or replacing oil plugged regulators is really annoying.

[PSOUZA]

Originally Posted by TinMan Trvlr

Is there anything short of the 4 hour clean out process posted earlier in this thread that can be done to eliminate the oil that may have dropped out of the propane in our main on board tank, and may be added to again by carry over oil included in the next propane fill? Clearing or replacing oil plugged regulators is really annoying.

The epic efforts of that procedure are an extreme example of what may be needed. Normally the oil absorbed by propane is a light grade and can be easily flushed by just solvent and compressed air. The addition of the drip pipe will not allow the oil of any weight to proceed past the trap point.

The properties of propane and how it absorbs oil and then releases it at low pressure is a complex subject for a forum such as this and people become hostile when confronted with the information. I don't care.

Propane will only dissolve so much oil. When it is saturated with oil, no more oil will travel with it. The propane sold will never, ever approach saturation and so the amount of oil in your tank will never reach saturation point.

During normal use, the oil will be in solution with the propane and pass out of the tank as a part of the propane vapor. As the pressure in the tank drops, while approaching empty, a very small amount of oil may drop to the bottom of the tank as liquid and remain there. This pressure would not allow appliance operation and thus normally would not occur. In any case it would dissolve back into the propane at the next recharge and not be an issue.

The vision of a layer of oil below the propane is a fantasy and will not happen.

Each subsequent propane fill will essentially scrub clean the tank walls and dissolve any remaining oils that will then pass out of the tank as vapor.

The oil only becomes an issue when the pressure drops in the regulator and the oil separates from the propane.

Not all regulators will react the same to the presence of the oils. Some regulators used by Winnebago WILL fail because of the oils. Avoid Gas Flo / Fairview Model GR-9959 at all costs.

Phil

[garyre]

Thanks very much for all the information and recommendations. I plan to install a drain cleanout with hopes to trap any unwanted fluids before getting to the appliances. Will check the systems within the next few weeks and hope to get the problems resolved.