Finding a gas leak

[roger wiegand]

Somewhere in our laundry/utility room there is a minute gas leak. If you close the door for a couple days the odor is noticeable, with the door open DW can smell it, I can't. This has been the case since the piping was installed. It passed the required pressure test for inspection.

I've been over every junction with soap solution and can't see any sign of a leak. The odor is so faint, I expect that the leak is very small (along with it having passed the pressure test). Between furnace, HW heater, gas dryer, and piping to the generator there are a _lot_ of joints.

Is there a more sophisticated leak detection system available?

[Tom M King]

I wonder if a refrigerant leak detector would work. Some are pretty sensitive. I never studied how mine works, but know it uses a heated diode. It can find a Very slow leak.

[Bill Dufour]

Call the gas company. they will do it for free with top quality equipment.
Bill D

[Bill Dufour]

Are you sure it is not urine or skunk? at very low levels they can smell similar.

[Ron Selzer]

Somewhere in our laundry/utility room there is a minute gas leak. If you close the door for a couple days the odor is noticeable, with the door open DW can smell it, I can't. This has been the case since the piping was installed. It passed the required pressure test for inspection.

I've been over every junction with soap solution and can't see any sign of a leak.


soap all fittings completely , probably a "sand hole" in one of the fittings, not a leaking thread joint
good luck
Ron

[Malcolm McLeod]

Might look at this (https://www.amazon.com/Combustible-Detector-Klein-Tools-ET120/dp/B074NBJ8XP/ref=asc_df_B074NBJ8XP/?tag=hyprod-20&linkCode=df0&hvadid=309803885710&hvpos=&hvnetw=g&hvrand=16011148901228622691&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9026921&hvtargid=pla-445731427643&psc=1). Or, talk to a home inspector, they may have one already?

A bit outside the scope of the problem, but if you work in confined spaces and worry about the atmosphere, try a clip-on 4-gas detector (https://pksafety.com/honeywell-bw-icon-4-gas-detector-lel-o2-h2s-co-icon-y-h/?utm_source=google&utm_campaign=smart%20shopping%20all&utm_medium=ppc&utm_terms=&gclid=CjwKCAjw4KyJBhAbEiwAaAQbE3O61Aakr47M01yLh-TZaN6o4gRtk-LsM_-42zZ8jP0S6m6DXgHNphoC5NMQAvD_BwE).

[Mike Soaper]

There's also the off chance that the gas valve/internal piping on the furnace, HW heater, gas dryer might be leaking.

[Kev Williams]

Just thinking out loud-- how about draping a cheap red shop rag around all the connections you can, and check them all a few days later for residual smell trapped in the fibers--

[Myk Rian]

There's also the off chance that the gas valve/internal piping on the furnace, HW heater, gas dryer might be leaking.

That's what I'm thinking also. The only thing I used to find gas leaks is water, a little Dawn, and a spray bottle.

[roger wiegand]

I think I'll try shutting the gas supply to the furnace and dryer off and see if the small goes away. I'm most suspicious of the dryer.

[Doug Garson]

I'm with Bill, call the gas company, gas leaks are not a DIY thing.

[Jerome Stanek]

It could be a pin hole leak in a length of pipe we had some bad pipe back in 1990 that had pin holes had to replace all the lines

[Dick Strauss]

Does the dryer use a flex line? If so, spray the whole length of it. They recommend you replace them when you replace the appliance because they develop leaks if flexed enough times.

[roger wiegand]

Yes, flex line on the dryer, new about three years ago when the dryer was installed. It has only been moved once that I can recall, but that is certainly a candidate. Shutting off the supply to the dryer will help me pinpoint that, but it will probably take a week or so tell. Again, the odor is very faint. We've been debating for years whether or not it's really there. (She's right again, of course. When will I learn?)

[Brian Elfert]

My gas utility will usually come within 90 minutes if a gas leak inside or outside of a house is suspected. I called once because I smelled gas in my utility room, but they found nothing. Another time I smelled gas near the meter. That time they found my natural gas generator was leaking and the technician red tagged it. It must have been leaking pretty good to be detectable by my nose outdoors. The gas valve in the generator was bad and not closing all the way.

Like others have said, call the gas company.

[Mike Henderson]

My gas utility will usually come within 90 minutes if a gas leak inside or outside of a house is suspected. I called once because I smelled gas in my utility room, but they found nothing. Another time I smelled gas near the meter. That time they found my natural gas generator was leaking and the technician red tagged it. It must have been leaking pretty good to be detectable by my nose outdoors. The gas valve in the generator was bad and not closing all the way.

Like others have said, call the gas company.

I agree. I had a leak and called the gas company - they were at my place before I could turn around. They take gas leaks VERY seriously.

And they have top quality sniffers to detect the leak.

Mike

[Dwight Rutherford]

Before calling the gas company I’d close the door for a couple of days so when they open it, they can smell the odor.

[Doug Garson]

Before calling the gas company I’d close the door for a couple of days so when they open it, they can smell the odor.
Not necessary, like Mike said they have top quality detectors, they don't need to be able to smell it. It would be interesting to hear whether they use ultrasonic detectors to hear the leak or oudor sniffers to detect it.

[John K Jordan]

Somewhere in our laundry/utility room there is a minute gas leak. If you close the door for a couple days the odor is noticeable, with the door open DW can smell it, I can't. This has been the case since the piping was installed. It passed the required pressure test for inspection.

I've been over every junction with soap solution and can't see any sign of a leak. The odor is so faint, I expect that the leak is very small (along with it having passed the pressure test). Between furnace, HW heater, gas dryer, and piping to the generator there are a _lot_ of joints.

Is there a more sophisticated leak detection system available?

I bought this one when I suspected a leak in a gas range. https://www.amazon.com/gp/product/B07BM1XWB8
It worked well when tested with an intentional leak. (gas range was ok)

BTW, is this natural gas or propane? If propane, is it from a tank that has been filled a few times? The reason I ask is I found out that the mercaptan can gradually settle to the bottom of a tank and a tank that has been refilled several times can build up a concentration. When the gas in the tank gets low, the odor becomes noticeable with normal use even when there is no leak. The propane dealer told me he's seen cases with a large tank where the whole house smelled like it would explode with a spark! In my case, the tank was very low and the odor made us suspect a leak in the cooktop. My tester and the expensive one the appliance tech used found no leak. The odor went away when the tank was filled.

If piped-in gas, nevermind!

BTW2, for others testing with a soap solution, the absolute best test I found is the solution sold for blowing bubbles. I bought a 5-lifetime supply (a couple of gallons) for $1 at Walmart at the end of the summer season one year. I use it on compressed air lines, tires, valve stems, tools, gas lines, etc. I apply a couple of drops with an eyedropper. Makes far better bubbles than anything I've mixed up from dish detergent and stays on the threads better too.

JKJ

[glenn bradley]

Gas Co. They are quick to respond and have the right gear. No charge where I live.

[Jason Roehl]

The gas company techs I’ve dealt with at work all say they can’t even smell it anymore. They use solution and electronic detectors.

You can get leak detection solution that is better than just a homemade soap solution—it’s much thicker (probably just a high concentration of glycerin). I think I use one at work called Big Blu.

[George Yetka]

Maybe the gas valve isnt shutting well in one of the pieces of gas equipment. If this is the case the gas company will turn it off and tell you to call an appliance repair guy.

[Frederick Skelly]

Call the gas company. they will do it for free with top quality equipment.
Bill D

This is what I was thinking. Or else your local fire department.

[John K Jordan]

This is what I was thinking. Or else your local fire department.

Fire department is a good idea.

I asked earlier if the gas was propane from a tank or a gas line from a utility but didn't see a response. My thinking was if it was from a user-owned propane tank there may not be a gas utility to call to check. I'll remember the fire department idea!!

[Wade Lippman]

I hope you have already solved your problem by now, but if you haven't...
The gas company will check for a leak for free. But understand that depending on the problem, but will either shut off your gas immediately, or give you a couple days to have it fixed.

[Bill Dufour]

My local gas company will loan out a $15,000 flir infared scanner for home owners to check insulation. I can only imagine how expensive their gas detection stuff is that they feel is too expensive to loan out.
Is the op a trained ng leak detector? does he know the likely leak spots, should the detector be manual or automatic pump. sniff to bottom or top of fittings etc. If the answer is "no" to any of these questions let the professionals do it for free.
Bill D

[John Terefenko]

I would look at the gas shut off valves. I had one that was older and had a small scent and if you put your nose next to it you detect it. Were the shut offs replaced and if not maybe they need to be.

[roger wiegand]

Natural gas from the utility company, not propane. I agree at this point that calling the gas company is undoubtedly the easiest thing to do. Though I have turned off the gas to the dryer and closed the door, will see if the smell has gone away.

This has been going on for about 7 years at this point, with DW thinking she could smell something sometimes and me mostly not. Both our plumbers and the town gas inspector have been in and out of the space when we installed a generator last year without noticing anything.

[Jim Becker]

While the nose can be a clue, the best way to test for gas leaks involves specialized equipment to do so. The utility folks carry those for such situations and the devices can help locate a leak exactly. I had our local utility do that as a courtesy a number of years ago at our old property when some changes had been made to the gas lines in the house and we had that occasional tiny "whiff" of the stuff they put in the gas that gives it the odor. (natural gas has no major odor on it's own) He was thorough and we did not find anything amiss...the "whiff" was probably a lingering artifact from the work that was done.

[Bill Dufour]

I do not know the numbers for natural gas, which is oderized and probably easier to detect but for Freon detectors 0.006 oz/yr (stationary) 0.1 oz/yr (moving per SAE J2791) is the minimum that they must be able to sniff out.
So the gas company is much better equipped and trained then your mark one nose.
Bill D

[Tom Stenzel]

When we moved into our house the furnace had just been replaced. Once in a great while I would smell gas but never found the leak.

One day my wife smelled gas and immediately called the gas company. DTE sent someone out with a leak detector but he didn't find any leak either.

When I redid the laundry room I also fixed some long standing code problems, like a gas flex line to the hot water heater and 6 (!) flex lines end to end for the dryer. Everything was redone with black pipe and some lines were relocated so they wouldn't hit someone in the head.

I found the leak. It was the cap on the end of the drip leg to the furnace. It had been screwed on hand tight but never had seen a wrench. I haven't the foggiest why it would leak sometimes and not others. It only took 18 years but by gum and by golly, I found it!

For leak detection at work we used Cool Snoop which had an antifreeze for outdoor use in winter. At home I use Dawn dish soap spiked with a bit of glycerin to make it sticky. If you want to buy something the stuff they sell in the toy aisle for making super bubbles works well.

-Tom

[Larry Frank]

I am surprised at the waiting to find the gas leak. One day it may get bigger faster and end up like pictures I have seen on TV. I just would not take the risk.

[Tom Bender]

Well here's how not to do it, but it worked for me.

The smell was from the stove after we moved it out and back. Soaped the line and all of the flex line but found nothing. Used a match and a tiny flame gave it away in the middle of the flex.

[Ron Citerone]

I would look at the gas shut off valves. I had one that was older and had a small scent and if you put your nose next to it you detect it. Were the shut offs replaced and if not maybe they need to be.

Worth a try, I have had 2 valves develop slight leaks in 35 years of living in my house.

[roger wiegand]

So had the gas company come (probably should have years ago), the tech found and patched three tiny leaks, each close to his lower limit of detection. We'll see if it passes DW's ultra-sensitive sniff test. One was a fairly loose cap on the drop going into the furnace that he put pipe dope on and retightened much more securely, the other two were at tees that would have been a substantial job to replace or re-tighten. He used an epoxy putty externally on those. I was surprised at that, but I assume the gas company knows what they are doing. The reading from his sniffer device dropped to zero after the putty was applied.

[Bill Dufour]

NG after the regulator pressure inside is 6-8 inches of water columm. I have plugged the pipe with my thumb when switching valves etc. I could not feel any pressure on my skin. It is under 1/2 PSI so epoxy is fine. Caulking or jb weld would probably be fine.
Glad you had the pro take a look.
Bill D