How do I install a Temperature Pressure Release (TPR) valve on my water heater and meet California Code requirements? My gas water heater is over 40 years old and does not have a TPR valve. The only outlets on the water heater are the inlet cold water and outlet hot water pipes on top of the water heater. There is no fitting on the side of the water heater. The water heater works fine and there is no leaking.

Unless California Plumbing Code has some odd requirement that existing water heaters must be retrofitted with a TPR valve, there is no need nor reason to add one now.

Your heater was installed to Code as it existed 40 years ago and as such would be 'grandfathered' and allowed to continue in use as it is.

Could we see a picture of your water heater. I don't think I have ever seen a heater without a T&P valve.

Hi John...

If you chase the cold water line back for a distance back from the water heater can you find anything that resembles a valve of any kind? You should be able to find a shutoff valve and perhaps you'll find an old fashioned type T&P valve... similar to a tankless coil relief valve on a boiler? Take a look... should find one.

ALL water heaters, since the beginning of time have required a relief valve of some kind, so at a minimum you should be able to find a tapping on the side or top of the heater to accept one. If no tapping present then I want to know more about the tank..? Are you sure this isn't a storage tank with a direct or indirect coil for heating the water? If so, then the T&P valve will be associated more so with the coil then with the tank... perhaps?

In my opinion, you've been lucky all these years and have not had any issues, but as that water heater gets older it only gets closer to failing and that failure could result in a dangerous situation so I would recommend that you install some kind of T&P valve in the heater or in the cold water piping into the heater.

Check out what can happen to a simple 12 gallon electric water heater if the system safety devices fail:

http://waterheaterblast.com/

Or click here for a version you don't have to download: http://www.youtube.com/watch?v=GF_Wrm-Ns0I

Finally, we have a great plumber out of California (Milo Dolezal), maybe he'll pop in and present his thoughts.

Any questions... let us know.

Mark

Harold, I was writing as you were. I completely agree!

"ALL water heaters, since the beginning of time have required a relief valve of some kind, so at a minimum you should be able to find a tapping on the side or top of the heater to accept one. "

Oh yeah?

I can see you didn't grow up with a coal stove in your kitchen and a water boiler attached to it for domestic hot water production... :)

No pressure relief devices on any of those tanks!

That was in the early 1950s through 1970s and worked something like this:

http://etc.usf.edu/clipart/63400/63472/63472_water_heater_lg.gif

http://www.inspectapedia.com/plumbing/RangeBoiler-Coal-030DF.jpg

You didn't run the coal stove in the summer so we only took cold baths.

Still run into the occaisional coal stoker with a hot water boiler tank with no TPR valves that are still in service in my region...

But I've been told I'm older than time, so I guess I predate most TPR valves anyhow... lol

You can post a pic directly using "go advanced/manage attachments".

If not a TPR, is there a rupture disc somewhere? Probably not.

Depending on the fitting (male or female NPT), I hope you should be able to add a TPR using a T fitting.

Either female-female-female or an odd fitting that's Male-female-female. Insert the TPR through the T and take the output of the water heater through the side port of the T.

Use either the weird fitting or a standard T so you don't have to use a nipple. I think the weird fittings are available, just not sure where.


This is the fitting idea I had: 3/4 FORGED STREET TEE - 127F-Street Tee by FittingConnection (http://www.fittingconnection.com/127F_Street_Tee-3_4_FORGED_STREET_TEE.html)

I echo Mark's comment: every pressurized tank has to have pressure relieve valve.

I am sure there is a inlet for PRV. It may be plugged as some installers plug it to safe few bucks. It can be either on top of the heater or on its side. If there isn't any plug than put 3/4" brass "T" on existing hot water nipple /outlet, install PRV to its side and reconnect hot water supply line on top of this T. That will satisfy the Code requirements. ( I think this is what KISS tried to suggest... )

The supply side would not make as much sense as the outlet side especially if the heater had a dip tube. This one probably doesn't, but I'd still put it on the outlet side.

This was exactly what I was suggesting. Use the Tee or special T such that the temperature sensor has the most penetration into the tank.

The top of the tank is preferable in any event.

This is what a Dip Tube looks like. The tube itself is attached to the bottom of the nipple and extends to the bottom of the heater... See the pic...

Unless California Plumbing Code has some odd requirement that existing water heaters must be retrofitted with a TPR valve, there is no need nor reason to add one now.

Your heater was installed to Code as it existed 40 years ago and as such would be 'grandfathered' and allowed to continue in use as it is.

You may be correct that I can fight this as grandfather case, but there actually appears to be a safety issue involved and I want to take care of the safety issue without buying a new water heater and do it per code. Thanks John

Could we see a picture of your water heater. I don't think I have ever seen a heater without a T&P valve.

Harold, I am attaching three photos, and have reduced the quality so they they transmit faster; let me know if you can not see something. You will see that the cold and hot piping connections are sound. Also, on top, there is a cap labeled ECO which covers wires going to a part on top of the water heater. Montgomery Ward is the maker of the water heater. Thanks, John

Hi John....

If you chase the cold water line back for a distance back from the water heater can you find anything that resembles a valve of any kind? You should be able to find a shutoff valve and perhaps you'll find an old fashioned type T&P valve...similar to a tankless coil relief valve on a boiler? Take a look...should find one.

ALL water heaters, since the beginning of time have required a relief valve of some kind, so at a minimum you should be able to find a tapping on the side or top of the heater to accept one. If no tapping present then I want to know more about the tank...?? Are you sure this isn't a storage tank with a direct or indirect coil for heating the water? If so, then the T&P valve will be associated moreso with the coil then with the tank...perhaps?

In my opinion, you've been lucky all these years and have not had any issues, but as that water heater gets older it only gets closer to failing and that failure could result in a dangerous situation so I would recommend that you install some kind of T&P valve in the heater or in the cold water piping into the heater.

Check out what can happen to a simple 12 gallon electric water heater if the system safety devices fail:

Water Heater Blast! (http://waterheaterblast.com/)

Or click here for a version you don't have to download: YouTube - Water Heater Blast (http://www.youtube.com/watch?v=GF_Wrm-Ns0I)

Finally, we have a great plumber out of California (Milo Dolezal), maybe he'll pop in and present his thoughts.

Any questions...let us know.

Mark

Harold, I was writing as you were. I completely agree!

Mark, please see the photos in my reply to Harold. Also, I checked the side of the water heater by removing the blanket and found no plugs. You are right that I am lucky that the water heater has lasted so many years. And, I am interested in the safety of the water heater. Thanks, John

The PRV port does not have to be on the top of the heater. In many cases it's on the right hand side near the top.

The most likely spot is on the right hand side under the insulating blanket and above the top strap shown in the picture. It would likely be located slightly behind the center line of the inlet pipes.

Idealy, the system should have a dialectric union (prevents corrosion) between the copper and the galvanized, but I would not change it now. A long life indicates that your water contains few ions which is a good thing.

The black port on this heater: http://www.hotwater.com/mediabank/media/res-gas/Effex.jpg is the TPR. That's a common height.

For now, just feel with your hands for a plug (bump) along that side near the top. It could be a flush plug, so if you don't find it, you'll have to remove the insulating blanket.

You can post a pic directly using "go advanced/manage attachments".

If not a TPR, is there a rupture disc somewhere? Probably not.

Depending on the fitting (male or female NPT), I hope you should be able to add a TPR using a T fitting.

Either female-female-female or an odd fitting that's Male-female-female. Insert the TPR through the T and take the output of the water heater through the side port of the T.

Use either the wierd fitting or a standard T so you don't have to use a nipple. I think the wierd fittings are available, just not sure where.

KeepItSimple, your idea is the same as my local hardware store recommended but he was not sure it would pass California code. I do not want to mess with the fittings on the hot water pipe unless I am sure that it is the way to go. I am afraid of messing up the old connection which is now sound. Thanks, John

I echo Mark's comment: every pressurized tank has to have pressure relieve valve.

I am sure there is a inlet for PRV. It may be plugged as some installers plug it to safe few bucks. It can be either on top of the heater or on its side. If there isn't any plug than put 3/4" brass "T" on existing hot water nipple /outlet, install PRV to its side and reconnect hot water supply line on top of this T. That will satisfy the Code requirements. ( I think this is what KISS tried to suggest...)

Milo, Why do you recommend a brass T as opposed to a galvanized one as is the piping connection (please see my photos to Harold's reply)? Thanks, John

This is what Dip Tube looks like. It is attached to the bottom of the nipple...See the pic...


Milo, I am not sure what this Dip Tube does. Does the white part extend into the water heater? Please see the photos I attached to Harold's reply. Thanks, John

1. Unwrap the thermal blanket. I bet you there will be plugged inlet that should have been used for T&P relieve valve.

2. That aluminum gas connecting tubing is against the Code. Replace it with new type gas flex connector to bring it up to Code.

3. You should use brass fitting between two dissimilar metals to prevent electrolysis.

4. The earthquake strap you show in your photos is no approved strap. You can buy approved strap in Home Depot or Lowe's. The stamp of approval is on the box.

5. The vent pieces should be secured with 3 sheet metal screws on each joint. No duct tape, please...

1. Check for a port under the blanket. Bet dollars to donuts it's there.

2. When two dissimilar metals are together with an electrolyte (dirty water) it creates a battery and corrodes. See: http://www.hammerzone.com/archives/plumbing/systems/components/union_de/intro.htm

3. Galvanized fittings rust from the inside. That's not something you want to happen. Brass won't corrode. Well, it does but creates a protective layer like aluminum. Besides galvanized for water just isn't used anymore. The sacrificial anode also limits corrosion. Won't get into details.

4. DIP tube et. al. HowStuffWorks "How Water Heaters Work" (http://home.howstuffworks.com/water-heater1.htm)

The hot water leaves from the top of the tank. If I dumped cold water in the top, it would layer and make the top layer of water colder.

If we inject water at the bottom of the tank, the top of the tank where the hot water comes out won't cool much, hence you get more hot water.

Still will bet dollars to donuts that the pressure relief port is on the side of the tank near the top.

Milo:

Do you think the flue elbow is backwards too?

The Gas cock is outdated too. That style develops leaks.

Picky compared to the lack of a TPR.

1. Unwrap the thermal blanket. I bet you there will be plugged inlet that should have been used for T&P relieve valve.

2. That aluminum gas connecting tubing is against the Code. Replace it with new type gas flex connector to bring it up to Code.

3. You should use brass fitting between two dissimilar metals to prevent electrolysis.

4. The earthquake strap you show in your photos is no approved strap. You can buy approved strap in Home Depot or Lowe's. The stamp of approval is on the box.

5. The vent pieces should be secured with 3 sheet metal screws on each joint. No duct tape, please...

Milo,

1. I have unwraped the thermal blanket at the suggestion of a city building inspector, and there is no plug

2. The photo is prior to me changing out to a flexible gas line

3. The brass T is a good suggestion

4. The earthquake straps actually are the type recommended by the city diagrams. The one you recommend would have been easier to install

5. You are correct, the vent pieces could use screws

Thanks, John

FYI guys. I found this interesting link about MW water heaters.

Montgomery Ward water heater - Page 2 - InterNACHI Message Board (http://www.nachi.org/forum/f22/montgomery-ward-water-heater-5351/index2.html)

They last.

1. Check for a port under the blanket. Bet dollars to donuts it's there.

2. When two dissimilar metals are together with an electrolyte (dirty water) it creates a battery and corrodes. See: Installing A Dielectric Union To Join Galvanized And Copper Pipes - Plumbing System Components (http://www.hammerzone.com/archives/plumbing/systems/components/union_de/intro.htm)

3. Galvanized fittings rust from the inside. That's not something you want to happen. Brass won't corrode. Well, it does but creates a protective layer like aluminum. Besides galvanized for water just isn't used anymore. The sacrificial anode also limits corrosion. Won't get into details.

4. DIP tube et. al. HowStuffWorks "How Water Heaters Work" (http://home.howstuffworks.com/water-heater1.htm)

The hot water leaves from the top of the tank. If I dumped cold water in the top, it would layer and make the top layer of water colder.

If we inject water at the bottom of the tank, the top of the tank where the hot water comes out won't cool much, hence you get more hot water.

Still will bet dollars to donuts that the pressure relief port is on the side of the tank near the top.

Kiss,

1. I unwrapped the blanket and there is no plug.

2 & 3 Good information on the corrosion and the brass T

4 I did not realize from your photo that the dip tube was long and for the cold water. I plan to leave the dip tube alone so I do not create problems.

I wish that you were correct that there was a plug on the side.

I think that this blog's recommendation for adding a T is a good suggestion. It makes sense. However, I would like to see that the T is approved by the California Code. Thanks, John

Try to take a flat screwdriver and lift that white plastic disk on top of the heater (see pic #3 ). See what's under it...

I am pretty positive the brace is not up to Code. What I see in your posted photos is a plumber's tape. Plumber's tape is used to support pipes. The approved earthquake brace has UL stamp of approval as well as stamp of approval from the City. (... these stamps can be visible on the bottom, right, of each box... )

If pressurized tank lacks required pressure relieve valve than one has to be installed by attending installer as close to the tank as possible.

Try to take a flat screwdriver and lift that white plastic disk on top of the heater (see pic #3 ). See what's under it....

I am pretty positive the brace is not up to Code. What I see in your posted photos is a plumber's tape. Plumber's tape is used to support pipes. The approved earthquake brace has UL stamp of approval as well as stamp of approval from the City. ( ...these stamps can be visible on the bottom, right, of each box...)

If pressurized tank lacks required pressure relieve valve than one has to be installed by attending installer as close to the tank as possible.

Milo,

The white cap is labeled ECO. Under it is a connection to the top of the tank with two electrical wires. I believe that it is some kind of high-limit switch based on my checks on Google.

Plumber's tape is required to be 3/4" x 24 gauge by the Water Heater Bracing Division of the State Architect. The pre-made straps you show would be much easier to install. Thanks, John

This document sums a lot of stuff up: http://www.lni.wa.gov/forms/pdf/620051a0.pdf

It basically says the TPR cannot be installed in the cold side.

No reducers in the TPR path. Should vent the same amount of water going in.

Must point down within 6" of floor with an air gap.

Can't have a threaded end.

The temperature sensor MUST extend into the tank.

The "T" in the hot water outlet seems like the only option. Technicly the insertion of the TPR sensing pipe makes the outlet smaller than the inlet, but that looks like it happens in the normal setup.

You would want to get the XL version of the valve (Extended length) http://media.wattswater.com/ES-10L-100XL.pdf

Full page of valves: Watts: Temperature and Pressure Relief Valves | Water Safety & Flow Control (http://www.watts.com/pro/_products_sub.asp?catId=64&parCat=294)

Just size it properly

From the date sheet:
Series 100XL
furnished with test lever and extension thermostat for installation
in the hot water outlet line or directly in the tank tapping.
Temperature sensing element must be immersed in the water
within the top 6" (152mm) of the tank. Male inlet and female
outlet. Temperature relief 210°F (99°C). Standard settings 75,
100, 125, 150psi (5.3, 7.0, 8.8, 10.6 bar).

They do suggest the "T" method and the XL version is 8" long. Measured from what - who knows. Who knows what the small one is (probably 6")

The last post here sums up all of the research: http://ths.gardenweb.com/forums/load/plumbing/msg0711464416597.html That post did say that the heaters had pressure rupture discs. They could be at the bottom of the tank and unseen.

Found the above last.

Key: Extended length probe and make at least 6" extend into the tank.

This document sums a lot of stuff up: http://www.lni.wa.gov/forms/pdf/620051a0.pdf

It basically says the TPR cannot be installed in the cold side.

No reducers in the TPR path. Should vent the same amount of water going in.

Must point down within 6" of floor with an air gap.

Can't have a threaded end.

The temperature sensor MUST extend into the tank.

The "T" in the hot water outlet seems like the only option. Technicly the insertion of the TPR sensing pipe makes the outlet smaller than the inlet, but that looks like it happens in the normal setup.

You would want to get the XL version of the valve (Extended length) http://media.wattswater.com/ES-10L-100XL.pdf

Full page of valves: Watts: Temperature and Pressure Relief Valves | Water Safety & Flow Control (http://www.watts.com/pro/_products_sub.asp?catId=64&parCat=294)

Just size it properly

From the date sheet:
Series 100XL
furnished with test lever and extension thermostat for installation
in the hot water outlet line or directly in the tank tapping.
Temperature sensing element must be immersed in the water
within the top 6" (152mm) of the tank. Male inlet and female
outlet. Temperature relief 210°F (99°C). Standard settings 75,
100, 125, 150psi (5.3, 7.0, 8.8, 10.6 bar).

They do suggest the "T" method and the XL version is 8" long. Measured from what - who knows. Who knows what the small one is (probably 6")

The last post here sums up all of the research: Hot water heater pressure relief valve - Plumbing Forum - GardenWeb (http://ths.gardenweb.com/forums/load/plumbing/msg0711464416597.html) That post did say that the heaters had pressure rupture discs. They could be at the bottom of the tank and unseen.

Found the above last.

Key: Extended length probe and make at least 6" extend into the tank.

Kiss,

I think that your information is winner. The diagrams and valve data are very helpful. I will have to see if I can get the TPR probe into the tank using the 8" probe. I do not want to disturb the water heater's hot water fitting and coupling, and I am not sure how far the TPR valve will be above the tank after adding the T. Your reference material is great. I will see if it works and if the inspector buys it. Thanks, John

"ALL water heaters, since the beginning of time have required a relief valve of some kind, so at a minimum you should be able to find a tapping on the side or top of the heater to accept one. "

Oh yeah?

I can see you didn't grow up with a coal stove in your kitchen and a water boiler attached to it for domestic hot water production...

No pressure relief devices on any of those tanks!

That was in the early 1950s through 1970s.
I was around back then and you're correct. Furnace Coils that's what they wrere called back then) didn't have a "pop-off valve" to relieve any pressure built up and In don't remember a T & P valve on the old gas fired units with the corkscrew copper coils inside. But I don't remember any explosions or blow ups from them either.
However, as a boy, I remember my father taking me to see the result of a water heater blowing up because there was no %T & P valve installed. The water heater was 8in the basement when it blew.
I blew through the first floor living room, through a second floor bedroom and out the roof. It landed a half block away in a vvacant field as flat as a pancake.
John,
If you don't have a T & P installed follow KISS advice and cut one in on the hot side outlet.
Good luck, Tom

I was around back then and you're correct. Furnace Coils that's what they wrere called back then) didn't have a "pop-off valve" to relieve any pressure built up and In don't remember a T & P valve on the old gas fired units with the corkscrew copper coils inside. But I don't remember any explosions or blow ups from them either.
However, as a boy, I remember my father taking me to see the result of a water heater blowing up because there was no %T & P valve installed. The water heater was 8in the basement when it blew.
I blew through the first floor living room, through a second floor bedroom and out the roof. It landed a half block away in a vvacant field as flat as a pancake.
John,
If you don't have a T & P installed follow KISS advice and cut one in on the hot side outlet.
Good luck, Tom

Tom, thanks for the info. I never heard about these problems before and I know that I will adding a TPR valve. John

FYI:

1. The Seattle Post-Intelligencer on July 28, 2001, reported on an electric water heater tank explosion where the pressures built up until the tank exploded. According to the article the force of the explosion blew the tank across six lanes of traffic and ended up in a parking lot more than 439 feet away.

2. In 1993, an older water heater exploded in a home in South St. Paul, Minn. The 200-pound tank shot through a floor, ceiling and roof like a missile to a height of 150 feet in the air. The explosion destroyed the home and injured two people.

3. In 1982 six children and one teacher were killed when a hot water heater exploded in the Star Elementary School cafeteria in Oklahoma City. Regulations were later enacted there requiring annual inspection of domestic hot water heaters in all public facilities.

4. Few years back in the 90's, in So. California, 100gln hot water heater blew up in El Toro restaurant killing one employee. It was determined the cause of explosion was absence of T&P valve on the hot water heater.

FYI:

1. The Seattle Post-Intelligencer on July 28, 2001, reported on an electric water heater tank explosion where the pressures built up until the tank exploded. According to the article the force of the explosion blew the tank across six lanes of traffic and ended up in a parking lot more than 439 feet away.

2. In 1993, an older water heater exploded in a home in South St. Paul, Minn. The 200-pound tank shot through a floor, ceiling and roof like a missile to a height of 150 feet in the air. The explosion destroyed the home and injured two people.

3. In 1982 six children and one teacher were killed when a hot water heater exploded in the Star Elementary School cafeteria in Oklahoma City. Regulations were later enacted there requiring annual inspection of domestic hot water heaters in all public facilities.

4. Few years back in the 90's, in So. California, 100gln hot water heater blew up in El Toro restaurant killing one employee. It was determined the cause of explosion was absence of T&P valve on the hot water heater.

Milo,

Thanks for the info. All along I have been trying to get the info that would meet code. I believe that the info that Kiss has give me will satisfy the code but I will have to see what the inspector says, which will not happen for about two weeks.

I expect to install the TPR valve next week. I hope that I do not have any installation leaks/problems especially in the connections to the water heater.

John

Good luck with your inspection. Please, let us know how you did... We are all learning as we go... Best Regards... Milo

Hey guys.. Can anybody guess what he has. Tom, I guess, is probably the best person to guess.

There is a copper pipe, a union and a galvanized threaded pipe.

What do you suppose is the joint between the copper pipe and the union?

Threaded?

Plumping solder won't stick to galvanized, but silver solder will.
If the coupling was factory, you'd expect it to be brass or copper.

Any guesses?

Can John care to take a guess. Evidence of threads?

Hey guys.. Can anybody guess what he has. Tom, I guess, is probably the best person to guess.

There is a copper pipe, a union and a galvanized threaded pipe.

What do you suppose is the joint between the copper pipe and the union?

Threaded?

Plumping solder won't stick to galvanized, but silver solder will.
If the coupling was factory, you'd expect it to be brass or copper.

Any guesses?

Can John care to take a guess. Evidence of threads?

Kiss,

I have always thought that the coupling had threads on both ends. I do not remember seeing solder on the bottom of the coupling but I never took a mirror to look under the coupling. I will see if I can get a look tomorrow.

But, no matter what is on the bottom of the coupling, I am not considering disrupting the bottom of the coupling (in fact, I am afraid of water heater connection problems when I will work on the top of the coupling). I am hoping to find a T, which is very short, that has a male thread on the bottom and a female thread on the top. The male end will go into the coupling, and the female end will accept the TPR valve. In total, I am hoping that the 8 inch TPR valve will extend an inch or two into the water heater. What do you think?

Thanks,

John

My thoughts. I think that piece of copper is a copper pipe, not a copper tube. Thus the outside diameter will probably be 1.05" rather than 7/8" which is for 3/4 copper tubing. This is assuming schedule 40 pipe.

I believe the joint at the bottom is threaded and it's 3/4 copper pipe with an OD of 1.05"

Now on current hot water heaters the dip tube is plastic, thus you can't heat the top fitting on the water heater.

Putting the TPR at the top of the copper pipe, I think, would give you the 4" requirement. An 8" probe seems to be the largest.

From the looks of it, you have 1" of copper pipe and an inch of union. Now add about 1.5" (guess) for a tee, so you have 1+1+1.5 or 3.5". Subtract from 8" you get like 3.5"

I think my estimates are wrong, but the ideal place is on the top of the copper pipe. Remember, I believe it to be pipe not tubing thus it's going to have a much thicker wall.

A brass or copper Tee, would be a good choice.

As for removal, I see a union in the picture, which also makes a nice lever arm.

I'd clean up the threaded area with a Dremel wire brush or wire brush.

I think I would use one vise grip that's good for tubing and a pipe wrench for the galvanized.

I'd hold the copper pipe with the vise grips and try to move the assembly and see which one loosens first.

I don't think I would heat the joint.

If the wrong joint moved, I'd tackle the union with a pipe wrench and the copper pipe with the vise grip. Something like: The Original? Curved Jaw Locking Pliers - Tools - IRWIN TOOLS (http://www.irwin.com/tools/locking-tools/the-original-curved-jaw-locking-pliers)

I am hoping to find a T, which is very short, that has a male thread on the bottom and a female thread on the top.
What you are looking for is a threaded brass street tee, (see image).
Good luck, Tom

My thoughts. I think that piece of copper is a copper pipe, not a copper tube. Thus the outside diameter will probably be 1.05" rather than 7/8" which is for 3/4 copper tubing. This is assuming schedule 40 pipe.

I believe the joint at the bottom is threaded and it's 3/4 copper pipe with an OD of 1.05"

Now on current hot water heaters the dip tube is plastic, thus you can't heat the top fitting on the water heater.

Putting the TPR at the top of the copper pipe, I think, would give you the 4" requirement. An 8" probe seems to be the largest.

From the looks of it, you have 1" of copper pipe and an inch of union. Now add about 1.5" (guess) for a tee, so you have 1+1+1.5 or 3.5". Subtract from 8" you get like 3.5"

I think my estimates are wrong, but the ideal place is on the top of the copper pipe. Remember, I believe it to be pipe not tubing thus it's going to have a much thicker wall.

A brass or copper Tee, would be a good choice.

As for removal, I see a union in the picture, which also makes a nice lever arm.

I'd clean up the threaded area with a Dremel wire brush or wire brush.

I think I would use one vise grip that's good for tubing and a pipe wrench for the galvanized.

I'd hold the copper pipe with the vise grips and try to move the assembly and see which one loosens first.

I don't think I would heat the joint.

If the wrong joint moved, I'd tackle the union with a pipe wrench and the copper pipe with the vise grip. Something like: The Original? Curved Jaw Locking Pliers - Tools - IRWIN TOOLS (http://www.irwin.com/tools/locking-tools/the-original-curved-jaw-locking-pliers)

Kiss,

You are probably correct that it is a copper pipe that attaches to the water heater. I took two photos, one with an inspection camera to see if there are any threads on the top of the copper. I believe that there is one thread showing.

I expect to have a local plumber look at the water heater on Friday. My discussion with the plumber today confirmed that I can use a T and the plumber is concerned about piping the TPR valve to a drain or outside. I had talked to a different plumber a few weeks ago who had no idea how to add a TPR valve and that is the reason I went through the safety inspection without the TPR valve; he said that I would have to buy a new water heater, but said that it would only last at the most 15 years, which may be less than the 40+ one I now have. The cost of having to buy a new water heater has created much anxiety for me, which subsided a few days ago when I realized from your comments and others that I could add a TPR valve.

I will let you know how things work out.. Thanks, John

There just might be a threads there. But hold it, there are threads into the tank too and they aren't corroded either. The top threaded joint would be the hardest and doesn't appear to be ideal.

A street Tee into the heater directly probably won't work because of the clearances. A short nipple of brass chrome plated copper or what you have would work combined with a regular Tee.

Add a dialectric union and your set to go from copper to galvanized. Copper and zinc (Galvanized) are really bad together based on this table Galvanic corrosion - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Galvanic_corrosion)

12 yrs is a pretty good life for a water heater. The only difference for a heater warrantied for 5 or 10 yrs is the cost of the warranty. They come off the same assembly line.

You really can't run the TPR discharge anywhere. It really has to go to within 6" of the floor without any threaded ends.

As usual there is an expensive solution or semi-expensive solution. It makes sense to install a water heater drip pan. In 55 yrs never had an issue, but the hot water supply and gas valve is set to pilot for extended vacations. I hot water line once broke under the basement floor.

The water heater drip pan can be plumbed to a drain, but not the overflow tube directly. It's not allowed to go up and out a wall. It can go down and out a wall, but not up. It also can't be set to scald someone either if it went off.

The Water Cop is a well known flood stopper. Watercop > Overview (http://www.watercop.com/overview.aspx) There are others and some that aren't wireless and some that are local.

In the grand scheme of things you have a drip pan under the heater with a sensor. The sensor turns off the water. Where. Could be the cold coming in from the street. You can have sensors at the water heater and laundry and both would turn off the cold water.

So, yes a water heater TPR failure means potential flood. A leaking tank means a potential flood.

I just picked up a wireless 4-sensor flood alarm, among other things. One sensor and alarm was like $30. I'm checking for a specific point of water entry along the foundation with the alarm in the bedroom until something can be done permanently to fix it.

Some ODD comments here: http://ths.gardenweb.com/forums/load/plumbing/msg0916420431108.html