Sorry to abuse this group - but I've yet to find another that has the
right "mentality" for doing things right. Something about a WW that
implies a certain character trait for striving for perfection, albeit
with a certain degree of cost consciousness.
ok.. onto the question
I am replacing my water heater. It's taller than the old one, so I
need to make some plumbing changes. The flue should be fine, and I
plan to use the existing gas line (black pipe into the heater - with a
short run of new flex - then into more black pipe (with a shutoff).
I'll wipe off the threads and apply a new batch of dope.
For the water lines, the old one had solid copper down to the heater,
with a compression fitting of sorts right at the heater. I don't
believe I can salvage that fitting. The new heater has male threads,
3/4" I believe.
Should I plumb with solid copper? The most challenging solution? Or
should I use some form of flex? Presumably I'd sweat on a male thread
connector to my solid copper and then use a flex line between solid
and heater. Is there a preference on flex? At HD, I see corrugated
copper and some form of stainless steel. The stainless can be
"pinched" and would seem to be "thinner" which to me implies more
likely to fail.
Any help much appreciated.
_IF_ that male-thread on the heater is copper, then 100% solid copper
*is* the way to go. Appropriate disconnect fittings are available -- may
have to check a _real_ hardware / plumbing-supply store -- or you back up
to the first elbow, and go from there, with a piece that has a female
thread sweated onto the end.
Note: unless it is a *big* water heater, it's probably a quote 1/2" NPT unquote
fitting, which _is_ close to 3/4" outside diameter.
If the heater fitting is anything other than copper, a "dielectric coupling"
is an _absolute_ requirement. You *don't* do metal-to-metal fittings on
water-carrying plumbing where the dissimilar metals come into contact.
Unless you want the joints to burst within a few years, that is. <grin>
Don't you love it when you read things like this *after* finishing a job?
My nipples were "heat traps" I think, and they were galvanized steel with
some sort of blue plastic stuff at the end. I used flex because the new
heater has a dramatically larger footprint than the original, owing to the
substantially improved insulation on the newer model. It would be a really
bitchy problem to solve with rigid pipe.
The flex has brass on either end, with that funky corrugated copper. So now
I've got copper to brass (not sure if the tin and whatnots mixed into brass
cause galvanic problems) and copper to brass/zinc/iron with some rubber and
plastic mixed in. Could be a mess. The blue plastic bits on the "heat
traps" might actually perform the function of some kind of of dielectric
junction, but I heard one of them make squeaky noises on the last turn,
which probably means I smushed through the plastic, and have brass on
OTOH, the old water heater had copper screwed directly onto some kind of
ferrous material, and it lasted for 30 years. I guess I'll worry about it
if it ever leaks.
Michael McIntyre ---- Silvan < firstname.lastname@example.org>
Linux fanatic, and certified Geek; registered Linux user #243621
A few thoughts on your installation...
Flex line is a poor choice. Aside from being expensive, it it unreliable.
1/2" copper is very easy to use; almost foolproof. 3/4", which you probably
have, is more challenging. Unless you can find someone experience to help
you, 3/4" might be too much to bit off for your first plumbing project.
The water heater I bought at HD had a big cautionary statement that you will
damage the heater by soldering the nipples on; a union is required. You
might want to check yours for that. (I didn't bother reading the
instructions until after I was done with the installation, and my soldered
nipples were fine, but that's another story.)
Good luck in whatever you do.
1) Why is it a poor choice? Some building codes may in fact require it,
for example in earthquake prone territory.
2) Upon what evidence do you base your assertion regarding the unreliability
of flex line?
In particular, a di-electric union is required. This is required to prevent
electrolysis from prematurely causing heater failure.
In addition to what other posters have written, I'd like to add this: Check
local codes. In earthquake-prone areas, they may *require* flex connections
for the water *and* gas lines. Other places may *prohibit* one or the other,
Doug Miller (alphageek at milmac dot com)
Nobody ever left footprints in the sands of time by sitting on his butt.
And who wants to leave buttprints in the sands of time?
Some local regulations require a licensed gas fitter to do the gas
connection. Frankly, for the matter of a few dollars, best to let
the pro do the connection and be safe. Likewise, the same gent can
deal with the Flue, and test for Carbon Monoxide afterwards.
This is one of those jobs that has legal issues, liability issues and
your home owners insurance coverage could be involved.
On Tue, 15 Mar 2005 00:25:25 -0700,
nospam email@example.com wrote:
Be careful to dot all the "i"s and cross all the "t"s legally with gas. If
something goes wrong and the house blows up and somebody gets killed and
you haven't covered all the bases then you might end up going up for
manslaughter--it's an unlikely scenario I admit but you know Murphy's Law.
First, check your local codes and make sure that they actually allow you to
work on gas. Then see what they say--among other things anything upstream
of the last cutoff may need to be pressure-tested--not difficult if you've
got the tools and know what you're doing but if you're never seen it done
before it might be a good idea to hire a gasfitter to do it the first time
and watch how he does it.
There should be a shutoff _before_ any flex--if the pipe leaks it's most
likely to be in the flex and if there is no shutoff upstream of the flex
then you have to turn the gas off at the meter until you get a chance to
change out the flex. Treat flex with the same degree of confidence that
you treat the hoses on a washing machine--only trust it so far. But you
should not need it with a water heater unless there is a serious
accessibility problem, and if there is then it would be better to address
the problem so that you can use solid pipe.
Unless there is a compelling reason not to, yes.
See comments with regard to flexible gas pipe. Unless there's a serious
accessibility problem there's no reason to use flexible water pipe with a
water heater--it doesn't get moved, it doesn't vibrate, there's no need for
it. If you need to offset the line a little there is bendable copper that
works fine. Others have commented on the issue of dissimilar metals, I'll
echo what they say--there are purpose made fittings for connecting
dissimilar metals in plumbing that provide isolation and prevent a galvanic
reaction. Use one if you need to.
Required or allowed? Seems to me that if it's required it should also be
required for furnaces, entrances, and various other places where more
movement and stress are expected than at the water heater connection.
I am not a contractor, but have owned and seen a lot of properties, in the
SF Bay Area. Flex is used in most or all of those applications you named,
such that I don't recall seeing anything else here.
Earthquake, expansive soils, etc. And progressive building codes. Tank
bracing is specified. So are quick shut-off valves. Fire after a quake is
a much bigger problem than the quake itself, both in property damage and in
danger to occupants. And the use of natural gas is almost universal.
What works for you in your areas, I don't know. Follow _those_ guidelines.
For example, we don't have to worry about frost heave or road salt
So, once you've turned the gas off at the stopcock and replaced
the flex-gas line, you turn the gas back on and it leaks, what
will you do? You do know how to check for leaks, right? (Hint,
don't use a match).
Note that a gas stopcock uses a special grease to prevent
leakage around the valve. It is a good idea to replace this grease
when you replace your flex line, especially if the valve hasn't
been turned in years, as if often the case. The valve can be disassembled,
apply the specialized grease liberally and reassemble the valve. If
you don't feel comfortable with this, just buy a new stopcock.
You may be able to call your gas supplier for a free hookup and leak
update on what was done
I called town hall. A permit and inspection is required. I called
the inspector, flex for water is ok. The county does not require a
permit/inspection for replacing a water heater, but the city does.
I removed the old heater and replaced with a new one. Same gallonage,
but different dimensions (taller, fatter).
I had to cut away some copper for the water. I sweated in a male
threaded insert to the solid copper and joined that to the heater with
corrugated copper flex. I had to bend the flex into a S shape. If the
S shape had been bigger, I guess that would have served as a heat
trap. Supposedly the heater has a diaelectric fitting. The copper
flex has a "rubber hose washer" inside it. Not exactly comforting. I
could probably sweat in solid copper if I have to. If I do redo this,
I will also redo some of the solid copper leading to the heater. It's
been jogged left and right several times that a) looks bad and b) I
For the gas line, I disassembled the old heater's flex (which as only
a few months old. It was put there by the furnace installer who moved
the heater when the new furnace was installed). The gas flex joined
solid black piping on the supply side with solid black piping on the
heater side also. I disassembled the necessary black pipe from the
old heater, cleaned the threads and inspected the pipe. It look OK
for re-use. I re-assembled the gasline -- blackpipe and flex using
thread sealant (pipe dope) on the black pipe joints and reattached the
flex with it's compression fitting (no dope here). I turned on the
shutoff valve, and using soapy water checked all the connections. No
I turned on the water, opened a faucet (blew out the air) and ignited
the pilot (that took awhile.. I'd say over a minute before gas hit the
igniter). The heater fired up and warmed the 50gal tank in about 1.5
While it was warming, I sweated on some fittings to make a copper line
from the expansion valve to floor drain.
I suppose I will go down to town hall and file for the permit and have
it inspected. The cost is like $55.
On Tue, 15 Mar 2005 00:25:25 -0700,
nospam firstname.lastname@example.org wrote:
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