[plumbing] Sealant on ground joint union?
#1
Le Mans Master
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St. Jude Donor '03-'05-'06-'07-'08-'11-'12-'13-'14-'15-'16-'17, '21
[plumbing] Sealant on ground joint union?
I'm planning to replace the natural gas shutoff valves near our furnace & water heater. They're over 40 years old, and I can detect a slight gas odor near them. I suspect the grease in them has hardened, or whatever.
Right after the shutoff valves, there are ground joint unions which I'll separate in order to remove & replace the valves. Do I put any kind of sealant on the mating faces of the ground joints? Anything special, standard pipe dope?
Thanks!
Right after the shutoff valves, there are ground joint unions which I'll separate in order to remove & replace the valves. Do I put any kind of sealant on the mating faces of the ground joints? Anything special, standard pipe dope?
Thanks!
#2
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When I replaced a water heater there was iron pipe carrying the gas supply and I used a special for the application putty to seal all joints.
Of course I used the soap bubble test after all was buttoned up to assure no leaks.
Check with a local plumbing supply store and get the appropriate sealant.
Of course I used the soap bubble test after all was buttoned up to assure no leaks.
Check with a local plumbing supply store and get the appropriate sealant.
#3
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I'm planning to replace the natural gas shutoff valves near our furnace & water heater. They're over 40 years old, and I can detect a slight gas odor near them. I suspect the grease in them has hardened, or whatever.
Right after the shutoff valves, there are ground joint unions which I'll separate in order to remove & replace the valves. Do I put any kind of sealant on the mating faces of the ground joints? Anything special, standard pipe dope?
Thanks!
Right after the shutoff valves, there are ground joint unions which I'll separate in order to remove & replace the valves. Do I put any kind of sealant on the mating faces of the ground joints? Anything special, standard pipe dope?
Thanks!
Pipe dope is not needed on the face of union, this is flared to mate w/ the other half of union. Be sure to check for leaks when finished.
Also do not use tephlon tape on pipe threads when working w/ natural gas. ( just thread sealant )
#4
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If you called the gas company and said you smell gas wouldn't they come and replace whatever with no charge ?
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There is nothing wrong with using teflon tape on natural gas lines as long as it is double density (yellow). It is important that neither thread compound nor teflon tape be allowed to get inside the piping. Leave the first 1 or 2 threads un-coated.
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St. Jude Donor '13-'14-'15-'16-'17
No sealant required on the ground joint.
You do need to use teflon or pipe dope on the pipe connections, if you have to remove them from the union to add the new valve.
Almost all gas valves these days are ball valves wih teflon seats for your valve replacement. But you can purchase new grease for your old lubricated plug *****.
LJ
You do need to use teflon or pipe dope on the pipe connections, if you have to remove them from the union to add the new valve.
Almost all gas valves these days are ball valves wih teflon seats for your valve replacement. But you can purchase new grease for your old lubricated plug *****.
LJ
#7
Le Mans Master
Not quite familiar w/ the term " ground joint unions"... But for a standard union ( threaded/sweat ) pipe dope is only required on the treads of pipe/nipple.
Pipe dope is not needed on the face of union, this is flared to mate w/ the other half of union. Be sure to check for leaks when finished.
Also do not use tephlon tape on pipe threads when working w/ natural gas. ( just thread sealant )
Pipe dope is not needed on the face of union, this is flared to mate w/ the other half of union. Be sure to check for leaks when finished.
Also do not use tephlon tape on pipe threads when working w/ natural gas. ( just thread sealant )
You may find that you want to replace that union while you have it apart. Yes they can be reused, but they do not always seal up as well once they have been used for years.
#8
Team Owner
No sealant required on the ground joint.
You do need to use teflon or pipe dope on the pipe connections, if you have to remove them from the union to add the new valve.
Almost all gas valves these days are ball valves wih teflon seats for your valve replacement. But you can purchase new grease for your old lubricated plug *****.
LJ
You do need to use teflon or pipe dope on the pipe connections, if you have to remove them from the union to add the new valve.
Almost all gas valves these days are ball valves wih teflon seats for your valve replacement. But you can purchase new grease for your old lubricated plug *****.
LJ
#9
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As Journeyman has indicated, make sure none of this pipe dope is deposited inside the piping or the "mating surfaces" of the union itself. The same practice should be followed with any threads.
Having "run" miles of screwed pipe myself...I ALWAYS coat the outside of the threads for the collar,(which is where "NO" is indicated, and should be YES) with pipe dope to insure the lubricatied joint enough torque to be firmly tightened. "Ground Joint" unions are typically made of forged steel, and most others are mallable iron. Most unions found in residental gas services are of the mallable iron type and are stamped "150", meaning they are rated for up to 150# pounds of pressure.
A very good question, I might add..
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#11
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Best sealant for metal pipe on gas lines is Rector seal # 5, by far and away. It is the yellow colored stuff that the gas companies have used for years. Teflon paste is OK but the yellow stuff is better.
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Pipe Dope or Thread Lubricant, which are the terms most pipefitters and plumbers use when talking about the compound used on pipe threads. I would suggest using one of these products on the threads on the "collar" of the union to allow for the lubricating of it's threads to help "tighten" the collar.
As Journeyman has indicated, make sure none of this pipe dope is deposited inside the piping or the "mating surfaces" of the union itself. The same practice should be followed with any threads.
Having "run" miles of screwed pipe myself...I ALWAYS coat the outside of the threads for the collar,(which is where "NO" is indicated, and should be YES) with pipe dope to insure the lubricatied joint enough torque to be firmly tightened. "Ground Joint" unions are typically made of forged steel, and most others are mallable iron. Most unions found in residental gas services are of the mallable iron type and are stamped "150", meaning they are rated for up to 150# pounds of pressure.
A very good question, I might add..
As Journeyman has indicated, make sure none of this pipe dope is deposited inside the piping or the "mating surfaces" of the union itself. The same practice should be followed with any threads.
Having "run" miles of screwed pipe myself...I ALWAYS coat the outside of the threads for the collar,(which is where "NO" is indicated, and should be YES) with pipe dope to insure the lubricatied joint enough torque to be firmly tightened. "Ground Joint" unions are typically made of forged steel, and most others are mallable iron. Most unions found in residental gas services are of the mallable iron type and are stamped "150", meaning they are rated for up to 150# pounds of pressure.
A very good question, I might add..
The OP probably has a 1/2" union that will be opened once in 15 years and likely replaced.
Why not? Double density teflon tape is deigned for gas lines.
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Pipe Dope or Thread Lubricant, which are the terms most pipefitters and plumbers use when talking about the compound used on pipe threads. I would suggest using one of these products on the threads on the "collar" of the union to allow for the lubricating of it's threads to help "tighten" the collar.
As Journeyman has indicated, make sure none of this pipe dope is deposited inside the piping or the "mating surfaces" of the union itself. The same practice should be followed with any threads.
Having "run" miles of screwed pipe myself...I ALWAYS coat the outside of the threads for the collar,(which is where "NO" is indicated, and should be YES) with pipe dope to insure the lubricatied joint enough torque to be firmly tightened. "Ground Joint" unions are typically made of forged steel, and most others are mallable iron. Most unions found in residental gas services are of the mallable iron type and are stamped "150", meaning they are rated for up to 150# pounds of pressure.
A very good question, I might add..
As Journeyman has indicated, make sure none of this pipe dope is deposited inside the piping or the "mating surfaces" of the union itself. The same practice should be followed with any threads.
Having "run" miles of screwed pipe myself...I ALWAYS coat the outside of the threads for the collar,(which is where "NO" is indicated, and should be YES) with pipe dope to insure the lubricatied joint enough torque to be firmly tightened. "Ground Joint" unions are typically made of forged steel, and most others are mallable iron. Most unions found in residental gas services are of the mallable iron type and are stamped "150", meaning they are rated for up to 150# pounds of pressure.
A very good question, I might add..
I am familiar w/ using "never seaze" on the collar threads, make it easier to get alittle extra tight.
#16
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St. Jude Donor '03-'05-'06-'07-'08-'11-'12-'13-'14-'15-'16-'17, '21
Many thanks for the replies!
I did buy the Rectorseal yellow, and will pick up new unions/joints as well, as Black94LT1 suggested. As I mentioned, this piping is 40+ years old, and the joints have already been apart once for a furnace replacement, and a couple of times for water heater replacements, so proabably worth replacing as long as I'm doing the valves.
This all started because I have to relocate a gas pipe to install a new range, and decided, while I have the gas shut off, to do those other valves also.
If you see no further posts from me after tomorrow, you'll know things didn't go well, and I should have hired a plumber.
Thanks again...
I did buy the Rectorseal yellow, and will pick up new unions/joints as well, as Black94LT1 suggested. As I mentioned, this piping is 40+ years old, and the joints have already been apart once for a furnace replacement, and a couple of times for water heater replacements, so proabably worth replacing as long as I'm doing the valves.
This all started because I have to relocate a gas pipe to install a new range, and decided, while I have the gas shut off, to do those other valves also.
If you see no further posts from me after tomorrow, you'll know things didn't go well, and I should have hired a plumber.
Thanks again...