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Photograph of gas lighting in a pre-1900 home Gas Pipe Clog Repair
Find & Fix Blocked LP Gas or Natural Gas Fuel Piping

Gas piping blockages or clogs in buildings for natural gas, LP gas, or propane:

How to find and clear or de-clog a blocked natural gas or LP gas pipe or gas line to an appliance or to a gas light.

In this article series on gas piping we provide descriptions and photographs of unsafe gas piping, indications of unsafe or improperly operating gas appliances, gas meters, and other gas installation defects are provided.

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Clogged Gas Pipe Diagnosis & Repair

Outdoor gas lamp near Moenchbruch Germany hunting lodge, Wikipedia 2017

Question: how do I un-clog the gas line to an outdoor gas lamp?

2017/04/22 Bill said:

How to unclog a natural gas line to my outside lamp.

This question and answer were posted originally at OIL LINE CLOGGING FIX

Above/left, an image of an outdoor gas light in Moenchbruch, Germany, Wikipedia 2017 cited atReferences or Citations

Reply:

For un-clogging a natural gas or LP gas pipe we start with some questions and include a safety warning.

First: anyone, even an expert, must be sure that the gas supply is turned OFF before fooling with gas piping at all.

What is the gas pipe material and diameter? If it's black iron pipe 1/2" or larger you or your plumber may be able to run a 1/4" diameter drain auger through the piping run.

RW Lyall Lyco plastic gas line riser at InspectApedia.comSmaller gas lines such as 3/8" or 1/2" flexible copper tubing or flexible stainless steel tubing are sometimes cleared by pushing a wire through the piping but at least with flexible tubing I'd prefer to use a smooth flexible plastic probe since scoring the interior of thin walled gas piping may cause damage or even a future point of corrosion and leakage.

But I'd be wary of ANY de clogging effort if the clog is due to rust, debris, or insects.

That's because any debris remaining in the gas line risks clogging a gas orifice or control - making the gas light unreliable or even possibly unsafe.

For an outdoor gas light or appliance whose gas supply line is buried, water leaking into the gas line can cause a blockage or can cause corrosion that blocks the line. Just 4" of water pressure can be enough to block a natural gas line.

Water in a gas pipe is almost certainly from a leak, not from "condensation" as the water content of LP or natural gas is very low.

Our image above illustrates a gas line riser intended for use with plastic gas piping. Produced by RW Lyall the Lyco® flexible riser seals and protects the plastic gas pipe where it enters or exits the ground. That's a common point at which water enters a buried gas line.

Below is an example of CSST, flexible corrugated stainless steel tubing used in some gas piping installations and described in detail at GAS PIPING, FLEXIBLE CSST.

Pro Flex CSST Gas piping at InspectApedia.comWatch out: If you find water in the gas line and it's corroded and/or the leak is not an obvious one easily repaired, that gas line should be replaced as it is unsafe, risking not just a gas appliance that doesn't work but also a gas explosion.

Your plumber may have or have access to a small-diameter pipe borescope that would permit inspection of the pipe interior. That would be worthwhile if you want to investigate the possibility of being able to avoid having to simply replace the line.

Plumbers often replace outdoor gas piping with continuous, waterproof, flexible polyethylene gas piping with risers at the pipe entry and exit points to keep water out of the system.

Producers of PVC or polyethylene gas piping and its connecting fittings include Dormont, DriscoPlex, GasTite, Endot, Pro-Flex, Lyall Lyco, Yellowpipe, and others.

Your plumber will find these at both plumbing suppliers and at building supply outlets such as Home Depot and Lowes.

So find out what has caused the clogged gas pipe. And replace the line if it contains water, rust, corrosion debris.

Research on clogged gas piping

 




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Reader Comments, Questions & Answers About The Article Above

Below you will find questions and answers previously posted on this page at its page bottom reader comment box.

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On 2021-04-16 - by (mod) -

Buried LP gas pipe line and gas regulator vent line (C) InspectApedia.com Daniel Friedman McKenzie@Yuvaraj,

Common causes of gas line clogging include debris from rust or moisture that condenses as water in the gas line; in a freezing climate water can also freeze in a line.

Watch out: when burying an LPG line between tank and a destination, such as an outdoor generator, take care to keep the buried lines as short as possible; condensation accumluating in dips in gas piping can cause the piping to become blocked by water or even to be damaged by freezing.

On 2021-04-16 by Yuvaraj

Liquid gas pipe line clogged what cause

On 2021-04-05 - by (mod) -

@Steve,

Your plumber would start by checking that there is gas supply, that the gas regulator is working, and if those seem OK she might look for blockages that are easily accessed by insects (like at a gas pilot), and for piping that might invite rust, debris, condensate that are not properly trapped.

If your gas piping is for LPG and there could be water or condensate in the lines the piping could be water-blocked, or in a freezing-climate, even ice-clogged.

Beyond that you'd need to shut off and disconnect the gas lines at the source and destination and try air pressure to see if there's flow.

Take a look at OIL LINE CLOGGING FIX https://inspectapedia.com/oiltanks/Oil_Line_Clog.php where we describe a CO2 cartridge oil line clog blast-out method that might work on some gas piping systems.

If the gas piping is clogged by corrosive rust flakes (in iron piping) or by "black dust" (corrosive oxides left by H2S in the gas supply) the pipes may need to be blown clean or in the worst case, replace.

Watch out: after working on your LPG gas piping be sure every connection and section is checked for leaks, lest you have a fire or explosion.

Interesting research on gas line clogging:


Zarinabadi, Soroush, and Amir Samimi. "Problems of hydrate formation in oil and gas pipes deal." Australian journal of basic and applied science 5 (2011): 741-745.
see a copy at

https://inspectapedia.com/plumbing/Gas-Pipe-Clog-Hydrate-Formatin-Zarinabadi.pdf

On 2021-04-04 by Steve

I believe I have a gas plug in my rv lpg line. Is there a way to check it out?

On 2020-11-27 - by (mod) -

Sorry I can't say what your gas engineer would have noticed or not but if your appliances are not working correctly it's worth having an expert come back to review it

On 2020-11-27 by Catherine

Thank,you danjoefriedman for your reply. Would the gas engineer have noticed that the gas line was blocked when he fitted my new cooker, or should I get him around again just to check this. Thank,you

On 2020-11-27 - by (mod) -

Catherine

The fact that both the old gas fueled cooker and your new one both seem to produce a too-weak flame suggests a problem with the gas supply system.

Your engineer may want to check that the gas delivery is adequate, including total piping lengths, diameter, elbows, and regulators. It's possible that there's a gas line blockage or that the primary or appliance regulators are not properly adjusted.

On 2020-11-27 by Catherine

My cooker was not heating up as it should, so being an old cooker I purchased a new one. I had a gas safety engineer to fit the cooker. I still find that the 3 small gas burners do not create enough heat. The grill cannot be turned high or low. It stays the same. The ovens take longer to cook than they should.

Could this be a gas line blockage.

Thank you

On 2019-06-11 - by (mod) -

The safe thing to do would be to turn off the gas supply at the point of entry. You're going to need to have a plumber remove rusted or clogged gas piping or if possible clean some of those sections. It's also possible that a drip leg or dirt line was forgotten and the piping arrangement. I don't know I can only guess because I can't see your installation.

On 2019-06-10 by Anonymous

I have a unit that on a flat slab which has been empty for three week. Before this gas was flowing throw the pipes to my water heater,stove,wall heater @ outlet for washer and dryer. Gas CO informed that they left gas on courteous for the new tenant. However I had my plumber replace the old water heater with a new one due to leaking. Now gas line is plugged.Meter for gas is open. Please help


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