Blob of pipe compound in gas line?

February 18, 2017 9:02 PM

Trying to figure out if there is a reason there is a glob of pipe compound in the gas line to my dryer.

I'm moving my gas dryer and needed to disconnect the gas line. When I got the line uncoupled from the unit, I found that the pipe into the dryer itself (the short pipe sticking out of the back) was blocked across about 50% of its diameter by a grey compound that I think is pipe compound to seal connections. It is like a grey putty. The blob extended about a quarter inch into the pipe - i.e., it was a fair sized blob, not just a little excess. My question is - is this a mistake or do you think it had a purpose like regulating/reducing the gas pressure? Installers from Home Depot did the connection a few weeks ago - I'm moving the dryer now. The dryer seemed to be working fine with the blockage in the line, so maybe it was intentional?

posted by Mid to Home & Garden (10 answers total)

I can't say for sure, but it doesn't sound right. Assuming the appliance end is an angled fitting with a screw connection, it isn't supposed to have dope on it at all. Only fittings that aren't self sealing are supposed to be doped.

I strongly recommend having it looked at by a plumber who knows what they are doing if there is any question, given the bad times a gas leak can cause.
posted by wierdo at 10:35 PM on February 18, 2017

The last thing you want is a bit of that in the burner orifice of your dryer, clean it out .
posted by hortense at 11:09 PM on February 18, 2017

There's no way they meant for that to be there. On every fitting in my house I can see a little pipe dope on the fittings, like where the shutoff valve joins the flexible line running to the fixture. It's not supposed to be inside the pipe.
posted by fixedgear at 4:40 AM on February 19, 2017

No, a blob of material (whatever it is) can't act as a pressure regulator. It might not have been hurting anything for the time being, but it shouldn't be there.
posted by jon1270 at 5:14 AM on February 19, 2017

It's not supposed to be there. Also, what kind of pipe or hose connects to your dryer? Unless it's plumbed with rigid steel pipe all the way (unusual for an appliance) it's likely a flare fitting which shouldn't even have dope on it.
posted by werkzeuger at 5:50 AM on February 19, 2017

It's most likely just an overenthusiastic (read: sloppy) application of pipe dope resulting from their desire to complete your install quickly and efficiently (read: get on to the next install).

Clean it out. When you reassemble anything involving gas, make sure that you thoroughly leak test the joints. The soap-and-water test is easy, but a quality electronic gas leak sensor is better if you can borrow one.
posted by jgreco at 6:29 AM on February 19, 2017

Response by poster: Thanks, seems like it was a mistake, I'm going to clean it all out. The hose to the dryer is one of those segmented steel semi-flexible things. It connects to a short rigid piece that sticks out of the back of the dryer. The blob was inside the short rigid piece, where it couples with the semi-flexible line. I thought it was a mistake but I wondered if it was intentional as a way to reduce the gas volume, which seemed silly, but the blob was big enough that it seemed weird to be a mistake.
posted by Mid at 6:35 AM on February 19, 2017 [1 favorite]

The grey goo was probably excess T-O-T. There are proper skilled plumbers who love using that stuff as well as whatever else is supposed to seal a joint - belt and braces reasoning - and it would not surprise me at all to find that a retailer's installers would get trained to use it but not necessarily trained to use it well.

It's always a bit hard to tell which way stuff is going to squeeze out of threads, and because the inside of a tube is always so much smaller than the threads on fittings that suit that tube, it doesn't take much excess sealant to squeeze a big blob into the tube if that's the way it ends up going.
posted by flabdablet at 9:50 AM on February 19, 2017

That's an easy problem, flabdablet. Properly applied, pipe compound never occludes the pipe. That's one reason it's preferred when you're doing hydraulic lines or when you are working with supplies that have orifices (like a gas line): chunks don't come off and gum up the works.

Pipe compound is *never* applied to the female fitting: only to the male fitting for the NPT style pipes used in water and fuel gas in the USA. The female fitting is left clean and dry.

I'm partial to Harvey's TFE Paste. The odor is more like linseed oil than petroleum distillates, and if I'm going to smell it all day I'm going to get a smell that I like.
posted by the Real Dan at 11:25 AM on February 19, 2017

Properly applied, pipe compound never occludes the pipe.

Quite so. My point is that expecting a discount retailer's installation crew to have anything approaching actual skill is probably unrealistic.
posted by flabdablet at 6:50 PM on February 20, 2017