Re: PLUMBERS - CPVC as dielectric coupling?
[Re: Stanton]
#3005311
01/14/22 06:02 PM
01/14/22 06:02 PM
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Joined: Jun 2004
Posts: 3,372 St. Charles, MO
wingman
Uncreative Title
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Uncreative Title
Joined: Jun 2004
Posts: 3,372
St. Charles, MO
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Is your house plumbed in copper or plastic?
The dielectric fittings are there to prevent galvanic corrosion between dissimilar metals. If your house is plumbed in copper pipe you don't want it in direct contact with the steel of the hot water heater. So the fitting electrically insulates the copper from the steel.
If your house is plumbed in plastic then dielectric fittings won't make any difference either way.
1969 Dodge Coronet Super Bee 383 A4 1970 Plymouth Road Runner 440 FC7 (sold)
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Re: PLUMBERS - CPVC as dielectric coupling?
[Re: wingman]
#3005347
01/14/22 08:39 PM
01/14/22 08:39 PM
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Joined: Jan 2003
Posts: 10,702 North Dakota
6PakBee
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 10,702
North Dakota
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Without knowing the answers to the questions that have been raised, all I can say is that if you are contemplating using female NPT PVC fittings, they are a leak waiting to happen.
"We live in a time when intelligent people are being silenced so that stupid people won't be offended".
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Re: PLUMBERS - CPVC as dielectric coupling?
[Re: wingman]
#3005404
01/14/22 11:16 PM
01/14/22 11:16 PM
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Joined: Jan 2003
Posts: 2,378 Massachusetts
Faust
OP
top fuel
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OP
top fuel
Joined: Jan 2003
Posts: 2,378
Massachusetts
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Is your house plumbed in copper or plastic?
The dielectric fittings are there to prevent galvanic corrosion between dissimilar metals. If your house is plumbed in copper pipe you don't want it in direct contact with the steel of the hot water heater. So the fitting electrically insulates the copper from the steel.
If your house is plumbed in plastic then dielectric fittings won't make any difference either way.
The plumbing is all copper, but the nipples on the water heaters are steel. I seem to be getting a lot of corrosion (green copper) near the water heaters. I thought to just put a CPVC female/male coupling between the nipples and the copper. Could the green just be an excess of flux?
Last edited by Faust; 01/14/22 11:17 PM.
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Re: PLUMBERS - CPVC as dielectric coupling?
[Re: Faust]
#3005479
01/15/22 10:32 AM
01/15/22 10:32 AM
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Joined: Jan 2003
Posts: 1,638 PA
70Duster
top fuel
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top fuel
Joined: Jan 2003
Posts: 1,638
PA
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The plumbing is all copper, but the nipples on the water heaters are steel. I seem to be getting a lot of corrosion (green copper) near the water heaters. I thought to just put a CPVC female/male coupling between the nipples and the copper. Could the green just be an excess of flux?
The green is either flux or a corrosion from a small leak. Just use teflon paste or tape and torque new copper threaded fittings onto the steel threaded fittings coming out of the water heater. The more fittings and different types of materials you use, the more opportunity there is for problems down the road. Never had an issue in four decades doing as described.
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Re: PLUMBERS - CPVC as dielectric coupling?
[Re: 70Duster]
#3005518
01/15/22 12:17 PM
01/15/22 12:17 PM
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Joined: Oct 2005
Posts: 8,859 Ontario, Canada
Stanton
Don't question me!
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Don't question me!
Joined: Oct 2005
Posts: 8,859
Ontario, Canada
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torque new copper threaded fittings How many foot/pounds are you recommending ??
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Re: PLUMBERS - CPVC as dielectric coupling?
[Re: Stanton]
#3005538
01/15/22 12:57 PM
01/15/22 12:57 PM
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Joined: Jan 2003
Posts: 10,702 North Dakota
6PakBee
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 10,702
North Dakota
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I use clear ammonia to clean solder joints after soldering to remove and neutralize any flux.
"We live in a time when intelligent people are being silenced so that stupid people won't be offended".
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Re: PLUMBERS - CPVC as dielectric coupling?
[Re: Stanton]
#3005567
01/15/22 02:03 PM
01/15/22 02:03 PM
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Joined: Sep 2003
Posts: 19,336 north of coder
moparx
"Butt Crack Bob"
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"Butt Crack Bob"
Joined: Sep 2003
Posts: 19,336
north of coder
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torque new copper threaded fittings How many foot/pounds are you recommending ?? crank it up 'till it strips or breaks, then back it off 1/2 a turn........................ [i couldn't help myself...... ]
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Re: PLUMBERS - CPVC as dielectric coupling?
[Re: Stanton]
#3005643
01/15/22 04:45 PM
01/15/22 04:45 PM
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Joined: Jul 2003
Posts: 712 New Jersey
Dartforforty
super stock
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super stock
Joined: Jul 2003
Posts: 712
New Jersey
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I've never known a plumber to clean a joint after soldering so the "green" could very well be from the solder. You can clean that off easily with a mild acid solution. The most effective is muriatic acid which will leave the copper as clean and shiny as the day it was made BUT be cautious with muriatic - the fumes are bad and it will burn skin. Dilute it and wear rubber gloves. Dip a rag in it and wipe the corroded area. Rinse with another rag soaked in clean water. The results are instant - no soaking and waiting required. I have been a plumber for 35 years, and yes I wipe every solder joint. We have never met but now you know att least one plumber who takes pride in his work. To answer the OP"s question, brass is a neutral metal which will not corrode when in contact with steel threads on a water heater. I would not mix CPV with the copper as a dielectric union. Ed
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Re: PLUMBERS - CPVC as dielectric coupling?
[Re: Dartforforty]
#3005649
01/15/22 05:10 PM
01/15/22 05:10 PM
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Joined: Oct 2005
Posts: 8,859 Ontario, Canada
Stanton
Don't question me!
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Don't question me!
Joined: Oct 2005
Posts: 8,859
Ontario, Canada
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brass is a neutral metal which will not corrode when in contact with steel threads on a water heater. Funny you should mention this - I was think this when I read the original post - most "threaded" connectors that copper solders into are brass. Yes, you can get copper, but brass are more common.
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Re: PLUMBERS - CPVC as dielectric coupling?
[Re: Stanton]
#3006130
01/17/22 07:25 AM
01/17/22 07:25 AM
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Joined: Mar 2005
Posts: 388 St. Louis, MO
BevoHoosier
enthusiast
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enthusiast
Joined: Mar 2005
Posts: 388
St. Louis, MO
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Don't most new residential water heater installs opt for flex-hose lines anyway? I just replaced an old water heater that had dielectric couplers on it and they were corroded solid anyway; just cut them off and sweated on normal fittings for the flex hose.
BMW
67 Dodge Polara 383
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