I'm replacing the natural gas shutoff valve to my water heater with a
1/2" ball valve with a red handle. The existing valve is 2.0" long; the
replacement one is 2-1/4", which means that one of the iron nipples
fitting into it must be shortened 1/4". Problem is, I don't know if the
existing ones are standard lengths or one is custom cut and threaded.

The visible length of the nipple going into the existing valve is
4-9/16". The visible length of the nipple between the output of the
existing valve and the union just in front of the heater is 2.50". The
actual lengths of these nipples are longer by the amounts that fit into
the threads of the valve and the adjacent fittings. How much should I
increase the length of a nipple over the distance between the end of a
fitting and valve to account for the threads that go into the fittings?

Standard nipples sold in Home Depot and Lowe's vary in length by 1/2".
That's why I think one must be custom cut and threaded.

One other concern is the lace of slack between the input gas supply and
the heater. This suggests that those nipples must be exact lengths so
when tightened there isn't a leak.

The final concern is using a brass valve with iron nipples. Is this okay
with natural gas?

Here's a photo of the setup:

http://tinyurl.com/pyppcg

Thanks,

Ray

Thanks, that's a very good photo. I don't really think the
extra quarter inch is going to hurt you that much. The pipes
by the water heater can be wrangled around, a little. The
brass valve may also take threads in more deeply than the
steel valve.

Brass valve on steel pipe is fine. Remember to use thread
sealant like Rectorseal #5 non hardening on the male
(external) threads only. It's not good to use teflon tape
cause pieces may flake off and get into the gas valve.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"Ray K" wrote in message
...
I'm replacing the natural gas shutoff valve to my water
heater with a
1/2" ball valve with a red handle. The existing valve is
2.0" long; the
replacement one is 2-1/4", which means that one of the iron
nipples
fitting into it must be shortened 1/4". Problem is, I don't
know if the
existing ones are standard lengths or one is custom cut and
threaded.

The visible length of the nipple going into the existing
valve is
4-9/16". The visible length of the nipple between the output
of the
existing valve and the union just in front of the heater is
2.50". The
actual lengths of these nipples are longer by the amounts
that fit into
the threads of the valve and the adjacent fittings. How much
should I
increase the length of a nipple over the distance between
the end of a
fitting and valve to account for the threads that go into
the fittings?

Standard nipples sold in Home Depot and Lowe's vary in
length by 1/2".
That's why I think one must be custom cut and threaded.

One other concern is the lace of slack between the input gas
supply and
the heater. This suggests that those nipples must be exact
lengths so
when tightened there isn't a leak.

The final concern is using a brass valve with iron nipples.
Is this okay
with natural gas?

Here's a photo of the setup:

http://tinyurl.com/pyppcg

Thanks,

Ray

On May 18, 8:31*pm, Ray K wrote:
I'm replacing the natural gas shutoff valve to my water heater with a
1/2" ball valve with a red handle. The existing valve is 2.0" long; the
replacement one is 2-1/4", which means that one of the iron nipples
fitting into it must be shortened 1/4". Problem is, I don't know if the
existing ones are standard lengths or one is custom cut and threaded.

The visible length of the nipple going into the existing valve is
4-9/16". The visible length of the nipple between the output of the
existing valve and the union just in front of the heater is 2.50". The
actual lengths of these nipples are longer by the amounts that fit into
the threads of the valve and the adjacent fittings. How much should I
increase the length of a nipple over the distance between the end of a
fitting and valve to account for the threads that go into the fittings?

Standard nipples sold in Home Depot and Lowe's vary in length by 1/2".
That's why I think one must be custom cut and threaded.

One other concern is the lace of slack between the input gas supply and
the heater. This suggests that those nipples must be exact lengths so
when tightened there isn't a leak.

The final concern is using a brass valve with iron nipples. Is this okay
with natural gas?

Here's a photo of the setup:

http://tinyurl.com/pyppcg

There's usually a bit of leeway in the pipes, so a small difference
can be accommodated by just moving the pipe a bit. It won't bend,
it'll just move out of the way.

If you need a specific length, the big box stores usually have a
threading machine in the plumbing aisle and the employee will cut a
nipple to length and thread it for you for a price.

R

On May 18, 5:31*pm, Ray K wrote:
I'm replacing the natural gas shutoff valve to my water heater with a
1/2" ball valve with a red handle. The existing valve is 2.0" long; the
replacement one is 2-1/4", which means that one of the iron nipples
fitting into it must be shortened 1/4". Problem is, I don't know if the
existing ones are standard lengths or one is custom cut and threaded.

The visible length of the nipple going into the existing valve is
4-9/16". The visible length of the nipple between the output of the
existing valve and the union just in front of the heater is 2.50". The
actual lengths of these nipples are longer by the amounts that fit into
the threads of the valve and the adjacent fittings. How much should I
increase the length of a nipple over the distance between the end of a
fitting and valve to account for the threads that go into the fittings?

Standard nipples sold in Home Depot and Lowe's vary in length by 1/2".
That's why I think one must be custom cut and threaded.

One other concern is the lace of slack between the input gas supply and
the heater. This suggests that those nipples must be exact lengths so
when tightened there isn't a leak.

The final concern is using a brass valve with iron nipples. Is this okay
with natural gas?

Here's a photo of the setup:

http://tinyurl.com/pyppcg

Thanks,

Ray

Why not simplify your installation by eliminating some of that hard
line and avoid the "hard line to hard line" issues

Replace the valve, come out of it with one of the nipples in your
current installation, follow it with a elbow and nipple down to a
couple Tee's ... add a flare male & use a SS flex line into the water
heater valve.

You probably have enough fittings in the current installation to do
all the rework.....just need two male flare to pipe adapters and a SS
flex line.

You'll be able to eliminate the union and not have worry about nipple
lengths or thread make up.

cheers
Bob

In article , fftt wrote:

You'll be able to eliminate the union and not have worry about nipple
lengths or thread make up.

Eliminating the union isn't a good idea. It's there for a purpose: to make
replacing the appliance easier. In some jurisdictions, it's required by code.

On May 19, 2:52*am, wrote:
On Mon, 18 May 2009 20:31:04 -0400, Ray K
wrote:



I'm replacing the natural gas shutoff valve to my water heater with a
1/2" ball valve with a red handle. The existing valve is 2.0" long; the
replacement one is 2-1/4", which means that one of the iron nipples
fitting into it must be shortened 1/4". Problem is, I don't know if the
existing ones are standard lengths or one is custom cut and threaded.

The visible length of the nipple going into the existing valve is
4-9/16". The visible length of the nipple between the output of the
existing valve and the union just in front of the heater is 2.50". The
actual lengths of these nipples are longer by the amounts that fit into
the threads of the valve and the adjacent fittings. How much should I
increase the length of a nipple over the distance between the end of a
fitting and valve to account for the threads that go into the fittings?

Standard nipples sold in Home Depot and Lowe's vary in length by 1/2".
That's why I think one must be custom cut and threaded.

One other concern is the lace of slack between the input gas supply and
the heater. This suggests that those nipples must be exact lengths so
when tightened there isn't a leak.

The final concern is using a brass valve with iron nipples. Is this okay
with natural gas?

Here's a photo of the setup:

http://tinyurl.com/pyppcg

Thanks,

Ray

You're taking this quarter inch way too seriously. *Tighten the
threads a few more turns and you used up the 1/4". *If worse comes to
worse, chisel a quarter inch of wood from the rafter above the pipe.
(from your picture, I see this is not an option)
But most likely one extra turn on 4 threaded points will compensate.
The water heater could be moved a very tiny amount too. *

Just DO IT. *It's not that critical.

LM


Or in the worst case, if you need it to the exact length for this or
any other application, HD will cut and thread their stock black pipe
to any length.

Flex line probably doesn't meet code for water heaters.
Necessary for stoves, as they are pulled out for cleaning.
WH just sits in one place. That said, when I moved into my
place, my furnace was supplied with flex line. Worked fine
for many years. I put in a 90+ efficiency furnace, and used
black iron to pipe it.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"fftt" wrote in message
...

Why not simplify your installation by eliminating some of
that hard
line and avoid the "hard line to hard line" issues

Replace the valve, come out of it with one of the nipples in
your
current installation, follow it with a elbow and nipple down
to a
couple Tee's ... add a flare male & use a SS flex line into
the water
heater valve.

You probably have enough fittings in the current
installation to do
all the rework.....just need two male flare to pipe adapters
and a SS
flex line.

You'll be able to eliminate the union and not have worry
about nipple
lengths or thread make up.

cheers
Bob

Flex has swivel ends, so the flex functions as a union. No
problem. Sort of no problem, that is. Unless you're trying
to meet code.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"Doug Miller" wrote in message
...
In article
,
fftt wrote:

You'll be able to eliminate the union and not have worry
about nipple
lengths or thread make up.

Eliminating the union isn't a good idea. It's there for a
purpose: to make
replacing the appliance easier. In some jurisdictions, it's
required by code.

It turns out that Home Depot cannot thread nipples as short as the
4-1/2" I needed. The outside diameter isn't the problem; it's the length
that must be inserted into the threader. (I don't know what that minimum
length is.)

The new valve is actually 3/8" (not 1/4") longer than the old. So by
playing with the nipples on both side of the valve, and not
overtightening, I was able to get a good fits using standard nipples,
which vary in 1/2" increments.

Thanks to all for your suggestions.

Ray

Ray K wrote:
I'm replacing the natural gas shutoff valve to my water heater with a
1/2" ball valve with a red handle. The existing valve is 2.0" long;
the replacement one is 2-1/4", which means that one of the iron
nipples fitting into it must be shortened 1/4". Problem is, I don't
know if the existing ones are standard lengths or one is custom cut
and threaded.
The visible length of the nipple going into the existing valve is
4-9/16". The visible length of the nipple between the output of the
existing valve and the union just in front of the heater is 2.50". The
actual lengths of these nipples are longer by the amounts that fit
into the threads of the valve and the adjacent fittings. How much
should I increase the length of a nipple over the distance between
the end of a fitting and valve to account for the threads that go
into the fittings?
Standard nipples sold in Home Depot and Lowe's vary in length by 1/2".
That's why I think one must be custom cut and threaded.

One other concern is the lace of slack between the input gas supply
and the heater. This suggests that those nipples must be exact
lengths so when tightened there isn't a leak.

The final concern is using a brass valve with iron nipples. Is this
okay with natural gas?


Uh, I think the only come in one size - but different colors. See he

http://www.bodyperks.com/

We had complete confidence in you. You made us proud.

(Hope you sealed the threads with Rectorseal, or something
similar.)

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"Ray K" wrote in message
...
It turns out that Home Depot cannot thread nipples as short
as the
4-1/2" I needed. The outside diameter isn't the problem;
it's the length
that must be inserted into the threader. (I don't know what
that minimum
length is.)

The new valve is actually 3/8" (not 1/4") longer than the
old. So by
playing with the nipples on both side of the valve, and not
overtightening, I was able to get a good fits using standard
nipples,
which vary in 1/2" increments.

Thanks to all for your suggestions.

Ray

On May 19, 4:14*am, (Doug Miller) wrote:
In article , fftt wrote:



You'll be able to eliminate the union and not have worry about nipple
lengths or thread make up.

Eliminating the union isn't a good idea. It's there for a purpose: to make
replacing the appliance easier. In some jurisdictions, it's required by code.



reread my post

if the jursidiction allows flex lines (SS or enameled) my suggested
changes will make replacing the w/h easier, safer & better.

The flex will serve the same function as the union and there wont be
any new pipe joints to break or make.

Right now he's totally hard plumbed, not a great situation unless
local code requires it.

If it was my installation, I re-plumb it, so both valves were
independent and at the "end" of their respective pipe runs.

Do it right, do it once.

cheers
Bob

On May 19, 4:14*am, (Doug Miller) wrote:
In article , fftt wrote:



You'll be able to eliminate the union and not have worry about nipple
lengths or thread make up.

Eliminating the union isn't a good idea. It's there for a purpose: to make
replacing the appliance easier. In some jurisdictions, it's required by code.

Not in SoCal...flex lines are allowed for water heater, stove &
furnace

btw the code is a minimum standard....

can anyone give a technical reason why a flex line would be ok for a
stove or bbq but not for a water heater?

cheers
Bob

For example, how do
they thread those 1.5 inch nipples where the threads on both ends
nearly touch? I never knew that.

Of course the factory thread-cutters have internal jaws.
I used to cut /thread pipe on an old Ridgid machine at a TruValu.