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chevynut
10-09-2013, 03:02 PM
I've been having a helluva time with the gas line in my shop. The old shop had a gas line from the meter at the house, underground into the shop attic, then to the heater in the shop with no gas shutoff. The guy who put the line in didn't install one at the meter. So I took the line apart where it enters the shop, installed a union and a shutoff valve. I took the elbow off where the line goes down to the heater and added a tee, and extended the line to the heater into the new shop with a few 10-foot sections of pipe and couplings, then installed all the fittings and pipe to get to the heater.

I needed to pressure test it and it has to hold 10 psi for 24 hours. It didn't. I figured it was probably the union I installed, so I tightened it a bit more. Still leaked down.

I climbed up into the attic to see if I could find the leak with some soap. Nothing where I looked.

So I decided to take off the union I installed where the line enters the shop and cap the line, just in case the problem was still the union. In doing that, I noticed the pipe coming out of the wall seemed a little loose. It shouldn't have been, because it should have gone straight to an elbow, then up into the attic. So I climbed up into the attic and removed the horizontal line. To do that I had to disassemble everything in the new shop....for the 4th time. Then I tried to tighten the vertical section. It just turned and turned, and never got tight. So I decided the elbow at the bottom was either broken, or something weird was going on. But I was now sure that was where the leak was since the nipple going into the shop was a little "floppy".

I cut a hole in the drywall near the floor inside the old shop, and I found out that for some STUPID reason I installed a union there 11 years ago. The 10-foot pipe wasn't long enough to get all the way into the attic back then, so I added a short piece at the bottom. Why I didn't use a pipe coupling I'll never know...must not have been thinking clearly. LOL!

Anyhow, I replaced the union with a coupling, and re-assembed the pipe all the way into the new shop. I was sure I had fixed the leak now, since the union had gotten loose somehow. So I re-assembled everything. It still leaked down.

So this morning I pressurized it with 30 psi to see what would happen. It dropped before too long. I climbed up into the attic again, and used soap to check the fittings. I found a small leak at a coupling I installed 11 years ago. So I tightened it. That loosened up the joint at the tee that I installed. Now I have to disassemble everything in the new shop again so I can tighten that fitting without loosening everything else.

I have put a lot of pipe dope on these threads. I cranked down on the pipe pretty hard. You would think it wouldn't be this hard to hold 10 psi. What a PITA...and I'm still not finished.

But I did get the vent done after disassembling it 3 times too. :)

warren57
10-09-2013, 08:21 PM
I've been having a helluva time with the gas line in my shop. The old shop had a gas line from the meter at the house, underground into the shop attic, then to the heater in the shop with no gas shutoff. The guy who put the line in didn't install one at the meter. So I took the line apart where it enters the shop, installed a union and a shutoff valve. I took the elbow off where the line goes down to the heater and added a tee, and extended the line to the heater into the new shop with a few 10-foot sections of pipe and couplings, then installed all the fittings and pipe to get to the heater.

I needed to pressure test it and it has to hold 10 psi for 24 hours. It didn't. I figured it was probably the union I installed, so I tightened it a bit more. Still leaked down.

I climbed up into the attic to see if I could find the leak with some soap. Nothing where I looked.

So I decided to take off the union I installed where the line enters the shop and cap the line, just in case the problem was still the union. In doing that, I noticed the pipe coming out of the wall seemed a little loose. It shouldn't have been, because it should have gone straight to an elbow, then up into the attic. So I climbed up into the attic and removed the horizontal line. To do that I had to disassemble everything in the new shop....for the 4th time. Then I tried to tighten the vertical section. It just turned and turned, and never got tight. So I decided the elbow at the bottom was either broken, or something weird was going on. But I was now sure that was where the leak was since the nipple going into the shop was a little "floppy".

I cut a hole in the drywall near the floor inside the old shop, and I found out that for some STUPID reason I installed a union there 11 years ago. The 10-foot pipe wasn't long enough to get all the way into the attic back then, so I added a short piece at the bottom. Why I didn't use a pipe coupling I'll never know...must not have been thinking clearly. LOL!

Anyhow, I replaced the union with a coupling, and re-assembed the pipe all the way into the new shop. I was sure I had fixed the leak now, since the union had gotten loose somehow. So I re-assembled everything. It still leaked down.

So this morning I pressurized it with 30 psi to see what would happen. It dropped before too long. I climbed up into the attic again, and used soap to check the fittings. I found a small leak at a coupling I installed 11 years ago. So I tightened it. That loosened up the joint at the tee that I installed. Now I have to disassemble everything in the new shop again so I can tighten that fitting without loosening everything else.

I have put a lot of pipe dope on these threads. I cranked down on the pipe pretty hard. You would think it wouldn't be this hard to hold 10 psi. What a PITA...and I'm still not finished.

But I did get the vent done after disassembling it 3 times too. :)


OK. so after some 45 years in the mechanical field, I offer the following thoughts:

The "couplings" that are on new pipe are actually no more than thread protectors. Actual couplings are thicker and don't stretch so easily.

Teflon tape (seals) your threads first (no tape on the first couple threads), then a coat of pipe dope (lube) over the tape. You'll never have a leak again!

On unions (no not the actual labor force!) lightly coat the face and/or seat of the union with pipe dope. Again you'll never have another union leak!

No unions in walls, attics, etc. (code issue)

Don't air test against a gas valve, they almost always leak by, blowing out your regulators (blew out every regulator in a Safeway store many years ago when I was an apprentice by doing this one!). Disconnect from any appliances and cap/plug for air test.

If system is dropping a few pounds of pressure that can happen went when air temp cools (at night).

Call one of your trifive friends in a nearby city to give you a hand next time! Buy full lengths of pipe and use my pipe machine to cut and thread as needed!
Let me know if you need a hand...

JT56
10-09-2013, 08:26 PM
That is definitely one that will make you pull your hair out. What type of pipe dope are you using? I have always use Teflon tape then apply the pipe dope.

ilike55s
10-10-2013, 06:23 AM
Hmmmm,,,you learn something new every day. I worked at an industrial place for 31 years and the pipefitters always used either the Teflon tape or the pipe dope but never the two together. There was one guy who always seemed to have some leaks and he was strictly a Teflon tape guy,,,,but after pressure testing showed a leak,,,he would always go back and get another round or two on the fittings and Presto,,,no more leaks,!! He just never would get all he could on the first go-round!
Our experiences were that the factory threaded fittings always had better sealing threads than the field threaded ones even with new dies in the threader.
Unions in a wall= danger and I think illegal by most building codes. Separate couplings or "collars" are heavier, higher rated than the ones that come with the full pipe joints, but I never figured out why,, AND you should not use the malleable or black fittings on pressure gas applications that some hardware stores stock. I do not know what the pressure rating is on the malleable fittings but if the lowest ratings on steel fittings is 2000#,, these can't be very high.
Chevynut,, you ain't got much time left for finishing your shop before the first snow flies, do you?

chevynut
10-10-2013, 08:20 AM
I stay away from the teflon tape whenever I can. My thought is that it has "layers" and is more prone to leaking than paste, and I have heard of people having problems like that. They say to use ONE wrap of tape. I used teflon pipe dope everywhere. Using the two together seems like overkill, and doesn't make sense to me but if it works for you, that's great. The pipe dope alone should work and I've never had problems like this before.

Like I said, I took the union out of the wall and replaced it with a coupling. I think I had a brainfart when I installed it...just saw something to connect two pipes together, and bought it. The only union I have now is outdoors at the gas valve.

This line only needs to hold about 1/2 PSI (7-12" of water) of gas so it doesn't need to be high pressure anything.

There's something weird going on here. I have factory threaded pipe. I put lots of pipe dope on the male threads, all the way around the pipe. I tighten them down securely. Some of these I've had to tighten extremely tight to get thing to line up...like "T"s and elbows. At one point I wondered if I was cracking the fittings or pipe, but I don't think that's happening.

Today I'm going to disassemble everything in the new shop again, and re-tighten the next fitting that I know is leaking a little and pressure test again with only the lines in the old shop. If it still leaks I'm going to keep taking it apart shorter and shorter until I find out WTF is going on.

My building permit expires on the 15th. I can get a free extension for 18 months, but I really don't want to. I've called for a final electrical inspection 3 days ago, but he hasn't shown up yet. Once that's done, I'm going to call for a gas and vent inspection and see what else he wants done before he signs off on the building final inspection. I have 20 bales of insulation ready to blow in and I think that's all he's going to want to see done. I have 3 doors to install, but I'm pretty sure he won't care about those being in yet.

warren57
10-10-2013, 08:43 AM
I stay away from the teflon tape whenever I can. My thought is that it has "layers" and is more prone to leaking than paste, and I have heard of people having problems like that. They say to use ONE wrap of tape. I used teflon pipe dope everywhere. Using the two together seems like overkill, and doesn't make sense to me but if it works for you, that's great. The pipe dope alone should work and I've never had problems like this before.

Like I said, I took the union out of the wall and replaced it with a coupling. I think I had a brainfart when I installed it...just saw something to connect two pipes together, and bought it. The only union I have now is outdoors at the gas valve.

This line only needs to hold about 1/2 PSI (7-12" of water) of gas so it doesn't need to be high pressure anything.

There's something weird going on here. I have factory threaded pipe. I put lots of pipe dope on the male threads, all the way around the pipe. I tighten them down securely. Some of these I've had to tighten extremely tight to get thing to line up...like "T"s and elbows. At one point I wondered if I was cracking the fittings or pipe, but I don't think that's happening.

Today I'm going to disassemble everything in the new shop again, and re-tighten the next fitting that I know is leaking a little and pressure test again with only the lines in the old shop. If it still leaks I'm going to keep taking it apart shorter and shorter until I find out WTF is going on.

My building permit expires on the 15th. I can get a free extension for 18 months, but I really don't want to. I've called for a final electrical inspection 3 days ago, but he hasn't shown up yet. Once that's done, I'm going to call for a gas and vent inspection and see what else he wants done before he signs off on the building final inspection. I have 20 bales of insulation ready to blow in and I think that's all he's going to want to see done. I have 3 doors to install, but I'm pretty sure he won't care about those being in yet.



OK, teflon seals the tread, dope lubricates it so the teflon doesn't peel. Overkill? not if it doesn't leak, redoing it with dope only 3 times....maybe .
One wrap, no way, try about 3-4 wraps ( in clockwise rotation so it doesn't peel off when tightening). As contractors believe me we experimented with multiple combinations until we virtually eliminated leaks, even when having apprentices with little training running screwed pipe. In the past 30-40 years I would venture to say 90+ % of all pipe installed by contractors contains teflon tape, without issues. Literally 10's of millions of pipe joints, world wide. But I'm not hear to promote or sell teflon tape, just hear to tell you what works for mechanical contractors. And you are right, that small of pipe should hold with no issues with pipe dope only.
The size pipe you are running could be tightened with channel locks and not leak, we always found the challenge being threaded pipe larger than 2". I've got a couple 48" pipe wrenches if you want to borrow them, but I'm not sure they will tighten down to 3/4" pipe. (ha ha)
As for teflon tape and pipe dope...Come on keep an open mind, try something new, you might be surprised how well it works and how much trouble it saves you!!


If you are using black malleable fitting (as you should for gas) they stretch, but nearly impossible to crack.

chevynut
10-10-2013, 03:07 PM
Well, I may have fixed it. :) I tightened up the fittings ( a coupling and a tee) by the heater in the old shop and the pressure is still holding 30PSI after 2-3 hours. I only need to hold 10 PSI for the inspector. But I have removed the drop to the old shop heater, and the plumbing in the new shop to the new heater and capped them off. I'll re-install that for the inspector.

The electrical inspector still hasn't shown up or called. I called for an inspection Monday. Maybe he thinks the government shutdown includes him. :mad:

Rick_L
10-10-2013, 06:10 PM
Doesn't matter if it's tape or dope, that stuff is just a lubricant so that you can tighten the joint enough to get a full interference fit on the pipe threads. Interference fit is the way that pipe threads seal.

I usually use two wraps of tape on a joint and don't tape the first thread or two. This avoids a piece of tape hanging out of the threaded joint, which can contaminate the system if it breaks loose.

Screw together unions aren't pipe thread, at least where the "union" is accomplished. They do have pipe thread where they attach to the pipe.

There's lots of Chinese fittings out there that are going to be a challenge to seal, or won't seal at all. Same with pre-threaded lengths of pipe made in China. And another challenge is finding pipe and fittings that AREN'T made in China.

On the other hand I installed a heater in the shop a few years ago and didn't have any problems with the pipe and fittings from the home improvement store.

chevynut
10-11-2013, 10:26 AM
WooHooo! 30PSI held since yesterday afternoon. I re-attached all of the plumbing in the new shop and pressurized it to 10PSI and have the gauge on it. I'm calling for an inspection for Monday.

Electrical inspector still hasn't shown up or called.....I called on Monday. I called his boss today to see what's going on, and I hope that doesn't piss him off. :eek:

chevynut
10-11-2013, 01:46 PM
Well, the inspector called me...he apparently didn't get either one of my calls. He said they go through VOIP and he works from his home computer. So something was wrong, and it may have gone to his spam folder. Anyhow, he came over and checked things out. Apparently I have a bad GFI because it wouldn't trip...he says he's not seen one in years. We took it out of the wall and confirmed it was wired correctly. So I need to replace that. He dinged me because I didn't have my panel labeled....forgot to do that. Also he said the new "energy code" required that I had a 3-way switch to my attic lights. I asked why I would need that for a storage attic since I didn't want to turn the lights off when I was up there. He said it was just a new code....he said don't worry about it. So he PASSED me!! I told him I'd address the GFI and the panel.

We got to chatting about cars and he has an old Studebaker. He wants to do something with the front suspension and has been looking at MII clips. I showed him the C4 setup in my Nomad and on the frame in the jig, and he's interested in doing one for his Studebaker. Seems like lots of these guys are into cars. The building inspector and I chatted about his car too when he came to check my insulation.

I just called for a heat and vent and gas line inspection on Monday. I hope all goes well because then I can blow the insulation in Monday night, and I THINK I can get a final next week. :)

chevynut
10-14-2013, 01:16 PM
Yes! Passed my gas line and heat and vent inspections. I was afraid I was going to get called for a 3/4" gas line feeding two heaters, but he didn't say a word about it. My son who works in HVAC said it would be okay, but I had a neighbor who added a shop and he was told his gas line was too small, even though it was 1 1/4" all the way from the house to the shop. Whew! I was worried about that.

All I need to do now is blow the insulation in, and install a handrail on the stairway, hook up the heater and thermostat, and put some pavers at the entrance and I can call for a final inspection.

Surprisingly, all of the inspectors I've dealt with on this project have been really cool.

Getting CLOSE!