About 3 years ago I installed a supply line from my home propane system to
my propane grill located on my wooden deck (obligatory wood reference ;-))
utilizing black pipe and Oatey pipe joint compound. A few days ago I walked
out on the deck and immediately noticed the tell-tale odor of propane.
First thing I checked was my grill thinking I had left it on, but it was
not. next, out came the squirt bottle of soapy water and I found small
bubbles being produced at 2 of the joints in the pipe. This pipe had not
been touched or moved in the 3 years it has been in place, so I am not sure
what caused the joints to leak. My question is should I use something else
to reseal the joints? Or just take the assembly apart, clean the threads
and reapply pipe joint compound and reseal? I assume (there is that word)
that just re-tightening the joint is probably not the best option. Do these
type of joints need any periodic maintenance, or is it just Murphy rearing
his ugly head? (since the leak was detected, I did shut off the supply
line, don't want someone lighting the grill and getting more than they
bargained for ;-)
I'm not an expert on this, but I don't think plain black pipe is the proper
material. My home propane was piped using copper tubing.
Materials allowed for yard piping include copper, PE (only pipe specifically
approved for exterior buried piping systems may be used) and factory machine
applied coated/wrapped black pipe with the joints of the black pipe wrapped
with ten mill tape which is half lapped and double wrapped
I ran the pipe from a connection that the home builder supplied on the back
of my house. The black pipe is a total of about 10-12 feet, terminating to
a propane approved hose (purchased at my local grill dealer) the hose then
goes from the black pipe to the grill. Sorry, I should have been more clear
in my OP.
Black pipe is fine for propane, most codes allow it.
As for the OP, be sure the gas is off disassemble the pipe, clean the
threads, and reassemble using a good pipe thread dope. On the job we use
Rectorseal with Teflon. Don't be afraid to tighten it good. Turn the gas
back on and check for leaks using dish soap and water.
That link gets a "connection refused". Generally speaking steel pipe is
preferred for gas. Some folks I know down in New Haven damned near blew up
their building when a copper gas pipe broke--the gas company wouldn't turn
the gas back on until the inspector approved the gas piping, and he made
them rip out _all_ the copper and replace it with black pipe, on a three
story building in the dead of winter.
Natural gas and propane have some different rules. Here in Putnam a house
did blow up when the gas company inspector broke a plastic line with his
probe while looking for a leak. He made it worse and it took out the house
and did major damage to the ones on each side of it.
Unless the pipe is totally exposed to the weather, and the rust and
corrosion build-up is VERY obvious, you should not experience any problems.
However, most people don't tighten NPT threaded joints sufficiently. You
should be able to turn in about 3-1/2 turns by hand, and you should tighten
an additional 1-1/2 to 2 full turns with a wrench. Additionally, teflon
tape is preferred over pipe joint compound (it never hardens).
Using teflon tape on combustion piping is an absolute no-no because
sooner or later a bit of teflon tape will break loose and find it's way
to the nearest orifice where it will plug it.
OTOH, teflon paste works quite well on combustion plumbing.
You would likely be better off posting to A.H.R. but as a start ....
The right move was to turn off the supply! You have a severe hazard
that needs to be fixed before ever turning the supply on again.
I can't make any more recommendation than to consult or even better,
hire a pipe fitter who is gas certified and make the installation
compliant safe and to reg's. I am guessing a complete disassembly with
a rebuild using properly rated materials and methods.
I don't believe the "Oatey pipe joint compound" you used is 'gas' rated
and likely the major cause for the failure you are seeing. Any 'black
iron' piping that is exposed to weather must be properly coated with a
protective layer of rust inhibiting paint sealer and usually is done on
site *after* all pressure leak-down tests are satisfactory.
Please, consult with a properly licensed expert. There could be well be
regulatory items limiting what you can DIY but regardless this is not an
area for trial and error.
George Gibeau wrote:
You're quite right there. Contrary to popular belief, pipe joint compound is
not meant to seal the joint. It's primary function is to lubricate the
threads so that they can be screwed together tightly enough to seal.
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