question on galvanic action
 

I moved to a house that is over a century old and noticed most of the upper
floor water lines to be
newer copper but the lower main lines galvanized steel

Won't this lead to rapid deterioration of the lower water lines?

I would also like to know general guidelines for avoiding galvanic action on
piping and so forth
I need to have a water heater installed andwas told to use fittings which
use a
mix of different metals in it's construction...
Why is this, and how does this negate galvanic action by merely being a
mixed metal fitting?

Thanks
Joe

I moved to a house that is over a century old and noticed most of the
upper
floor water lines to be
newer copper but the lower main lines galvanized steel


Won't this lead to rapid deterioration of the lower water lines?


"I would also like to know general guidelines for avoiding galvanic
action on
piping and so forth
I need to have a water heater installed andwas told to use fittings
which
use a
mix of different metals in it's construction...
Why is this, and how does this negate galvanic action by merely being a

mixed metal fitting? "

This is a long and complex subject. If you do a google search for
galvanic and water heater you should find lots of threads. The idea of
the different metal couplings is that the two different metals are
seperated by an insulator, making it a dielectirc union. That way,
there is no current path between the different metals. However, there
is still a path for current through the water itself. And then there
is the issue of ground path bonding. Normally, all metal water pipes
are tied together within a house and tied to ground. Inserting a
dielectric coupling breaks that path. If you jumper over it, then you
defeat the purpose of the dielectric union.

I have heard mixed reports in practice as to whether using these unions
on a water heater makes things better or worse. And I think the answer
depends on a lot of things. Most water heaters don't have them and the
plumbing connections seem to last just fine. Mine doesn't. I replaced
the original gas water heater at about 12 yrs, which is pretty normal.
No evidence of corrosion at the fittings.

"MW" wrote in message
...
I moved to a house that is over a century old and noticed most of the
upper
floor water lines to be
newer copper but the lower main lines galvanized steel

Won't this lead to rapid deterioration of the lower water lines?

I would also like to know general guidelines for avoiding galvanic action
on
piping and so forth
I need to have a water heater installed andwas told to use fittings which
use a
mix of different metals in it's construction...
Why is this, and how does this negate galvanic action by merely being a
mixed metal fitting?

Thanks
Joe



This is a lay person response based on 30 years of personal experiences.

The problem is greatly overstated.

Most problems will occur at the point of joining the different metals.

Purity is best but not always practical. Keep the transition in a visible
location.

Your water heater will die in about 10 years or 1 year after the warranty no
matter what you do or don't do.


Colbyt

Just a thought. Galvanic action is a serious problem for boats in salt
water, and maybe more of a problem if there is a high mineral content
in your water. Consider converting to plasitc pipes for DIY plumbing.
Check your electrical ground, you may need to install a new ground rod
or plate.

JohnK

MW wrote:
I moved to a house that is over a century old and noticed most of the
upper floor water lines to be
newer copper but the lower main lines galvanized steel

Won't this lead to rapid deterioration of the lower water lines?

I would also like to know general guidelines for avoiding galvanic
action on piping and so forth
I need to have a water heater installed andwas told to use fittings
which use a
mix of different metals in it's construction...
Why is this, and how does this negate galvanic action by merely being
a mixed metal fitting?

Thanks
Joe

As noted the problem is complex. Part of the formula is the water
(acidity salt content etc.) electrical grounding and others. The short
answer is if the plumber did the job right, it is not a problem. The problem
comes up when the plumber takes shortcuts or the home owner does not know
better. It seems you do.

--
Joseph Meehan

Dia duit

Just an aside...

I have installed a ground rod and wire to solve the problem of
grounding via waterpipes but I just read in fine homebuilding mag of a
person who stated that galvanic action was so important you should not
use galvanized hangers of any type with copper spouts (I have copper
spouts)
...and brought up the statement of a 'nomenclature or hierarchy of
metals which should be used in conjunction with each other to avoid
galvanic action and it set me to thinking on the bit of galvanized main
line I have and the connections to my copper lines as well

Thanks for the info and link..
I will hit the link provided

Joe


PS: The union for the new direct vent water heater I intend to install
doesnt have dielectric properties but merely a transition of metals
within itself --strange I thought as that would only exacerbate the
problem I would think unless the particular metal plating was of a
particular order of metals
that was related to that "hierarchy" I read of
-
confused but willing to learn

"Colbyt" wrote in message
news:f8OdnaBZbZ9Lc-rfRVn-
Your water heater will die in about 10 years or 1 year after the warranty
no
matter what you do or don't do.

I've been in my house for 16 years. I guessed the water heater was many
years old when I moved in. I just replaced it.

Bob

"Jose" wrote in message
oups.com...
Just an aside...

I have installed a ground rod and wire to solve the problem of
grounding via waterpipes but I just read in fine homebuilding mag of a
person who stated that galvanic action was so important you should not
use galvanized hangers of any type with copper spouts (I have copper
spouts)
..and brought up the statement of a 'nomenclature or hierarchy of
metals which should be used in conjunction with each other to avoid
galvanic action and it set me to thinking on the bit of galvanized main
line I have and the connections to my copper lines as well

Thanks for the info and link..
I will hit the link provided

Joe


PS: The union for the new direct vent water heater I intend to install
doesnt have dielectric properties but merely a transition of metals
within itself --strange I thought as that would only exacerbate the
problem I would think unless the particular metal plating was of a
particular order of metals
that was related to that "hierarchy" I read of

I just installed a new water heater - it came with dielectric nipples.

I was told recently that brass connections between copper and galvenized
steel will work as well as isolating junctions. I also was told that bonding
the copper to the iron with a wire when connected with isolating junctions
does not cause corrosion. Opinions?

Bob

"I also was told that bonding
the copper to the iron with a wire when connected with isolating
junctions
does not cause corrosion. Opinions? "

I don't see how that's possible. The classic experiment showing
galvanic action is to take two different metals, place them in an
electolyte, and measure the voltage between them. When connected by a
wire, the less noble metal will corrode. This is them method used to
protect boats. All the underwater metal is bonded together and zinc is
used as the sacrificial anode. At best, I would think using a bonding
wire across the dielectric unions would move the point of corrosion and
perhaps distribute it over a different area.

this is alt.home repair guy!

















Agent 69 wrote:
MW wrote in alt.drugs.hard:

I moved to a house that is over a century old and noticed most of
the
upper
floor water lines to be
newer copper but the lower main lines galvanized steel

Won't this lead to rapid deterioration of the lower water lines?

I would also like to know general guidelines for avoiding galvanic
action on
piping and so forth
I need to have a water heater installed andwas told to use fittings

which
use a
mix of different metals in it's construction...
Why is this, and how does this negate galvanic action by merely
being
a
mixed metal fitting?

Thanks
Joe

Sorry officer, we can't help you here...

Agent 69
alt.drugs.hydromorphone