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Ron3rd's avatar
Ron3rd
Explorer III
Mar 26, 2021

Black oil in propane line?

I'm going to be installing a propane quick connect on our new to us fiver which to my surprise does not have one.

The hard line I'm tapping into appears to be 1/2" gas pipe. I've found a convenient tee with a plug to tap into. I've removed the plug which was facing DOWN and some smelly black oil came out; maybe a teaspoon or so. Is this anything to be concerned about?

Also, can I install my quick connect also facing DOWN off the tee without fear oil flowing into the quick connect?
  • the oil is pretty normal in threaded steel pipe, it is cutting oil and used when threading the pipe. unless you stand the pipes up vertical for a while after threading it will always be there, best is to install a sediment trap or drip leg as in the above post.
  • Ron3rd's avatar
    Ron3rd
    Explorer III
    Boon Docker wrote:


    Thanks for the info folks. I can easily install a short pipe like shown.
  • ScottG wrote:
    All my QD's (3) are pointed straight down. The tiny amount of oil is just passed along to the BBQ or what ever and in 16 years has never been an issue.


    I suspect it depends on when and where you get your propane filled as to how much of a risk you run about getting too much oil in the load. I've got a 3 year old RV that I bought new and after the second year I had to replace the gas regulator because it had fouled up with oil in the lines. (At that point I'd probably only had the tank refilled about 3 times too.) I know a number of others who have had the same problem and some now even carry spare regulators, although I think that's an over-reaction to the problem.
  • All my QD's (3) are pointed straight down. The tiny amount of oil is just passed along to the BBQ or what ever and in 16 years has never been an issue.
  • wnjj's avatar
    wnjj
    Explorer II
    Seems like the tee may have been there as an oil trap. If you tap off of it, include another tee (facing down) in the line you add.
  • midnightsadie wrote:
    they make a fitting called a street L that would give a 90deg turn right at the fitting.


    But that would still mean that any oil in the line would go down the ell and still get in the quick connect.
  • they make a fitting called a street L that would give a 90deg turn right at the fitting.
  • It’s common to find a little oil in the propane lines . If it’s possible to turn the T on its side that would be the preferred way in my opinion. As long as you don’t cause a leak on the existing joints or a twist in the copper appliance feed line further along.
    Test any changes by spraying soapy water on all the joints!

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