Propane goop and keeping fridge going during travel

[hshovic]

I had to replace my regulator because of oily goop in it (25,000 miles on the trailer). Symptoms were low pressure at times. The RV repair place thought it was from overfilling a tank, getting liquid propane in the line, where it evaporates and leaves oily residue from the various additives. Another opinion by the gas company is that liquid propane gets sloshed around during travel if the gas valves are open, doing the same thing. Actually,they told me since RV's don't generally have sediment traps in their gas appliances, it could possibly puddle in the appliance making a fire hazard.

Both seem likely, so it is a reason to turn off the gas during travel at the tank. And another reason to make sure the propane fillers always open the bleed screw to make sure no overfill occurs.

[Wabbiteer]

Oily goop? It does not require liquid sloshing, post regulator lines running at atmospheric pressure can get black wax oiled from just one bad batch of propane. Your Northern area true propane content is probably a minimum of 90% with maximums of 5% butane and 5% propylene - there should be no other additives, thats a touch of spin control from the suppliers -- but liquid propane is an excellent solvent and improper handling or equipment in the supply chain or gives a nasty product. If you replaced the regulators you could still be carrying a problem in your tanks...

[RickDavis]

I have found a lot of oily goop in the bottom of tanks when replacing valves. I have alway assumed that this from the additive that is used to give propane its onion smell.
I have also noticed as you get to the bottom of the tank I will get odor from pilot lights etc. It disapears as soon as the tank changes over.

[Ganglin]

There was an RV article that I read Monday that mentioned this problem to a limited extent. Their recommendation to help prevent line build up was to always shut off the tanks and let the appliances burn off all the gas in the lines. Something to think about anyway...

[Jammer]

Originally Posted by hshovic

I had to replace my regulator because of oily goop in it (25,000 miles on the trailer). Symptoms were low pressure at times. The RV repair place thought it was from overfilling a tank, getting liquid propane in the line, where it evaporates and leaves oily residue from the various additives.

That's contaminants, not additives. Otherwise, they're probably right. Since the contaminants don't vaporize, they accumulate over time in the tank.

Another opinion by the gas company is that liquid propane gets sloshed around during travel if the gas valves are open, doing the same thing.

The vapor withdrawal port is located in a place where it is nearly impossible to get any significant amount of liquid propane into it by splashing from a properly filled tank.

Actually,they told me since RV's don't generally have sediment traps in their gas appliances, it could possibly puddle in the appliance making a fire hazard.

They're called drip legs, not sediment traps. Since RVs have a piping system designed so that the piping extends vertically from under the trailer to each appliance, any contaminants are trapped in the pipe below the trailer just as effectively as they would be in a drip leg.

Both seem likely, so it is a reason to turn off the gas during travel at the tank. And another reason to make sure the propane fillers always open the bleed screw to make sure no overfill occurs.

They should not only use the bleed screw, they should weigh the tank.

[Jammer]

Originally Posted by RickDavis

I have found a lot of oily goop in the bottom of tanks when replacing valves. I have alway assumed that this from the additive that is used to give propane its onion smell.
I have also noticed as you get to the bottom of the tank I will get odor from pilot lights etc. It disapears as soon as the tank changes over.

Methyl mercaptan, the odorant in propane, does not itself form an oily goop, though it does have a somewhat lower vapor pressure than propane leading it to accumulate and have a higher concentration towards the end of the tank.

[Jammer]

Originally Posted by Ganglin

There was an RV article that I read Monday that mentioned this problem to a limited extent. Their recommendation to help prevent line build up was to always shut off the tanks and let the appliances burn off all the gas in the lines. Something to think about anyway...

I think this is nothing but FUD. If it's really a problem it could be solved easily enough by forming a loop in the pigtail from the tanks to the regulator.

[barts]

From what I've been told by fire effects folks who go through _lots_ of propane, some suppliers have significant oil vapors in their propane.... not much of an issue for a 2" dump valve for fireballs, but for a small orifice at .5 psi this could be problematic. It does help reduce tank rusting w/ steel tanks, I guess.

- Bart