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-   -   Is a themal expansion tank really needed? (https://www.askmehelpdesk.com/showthread.php?t=7988)

  • Feb 24, 2005, 09:40 AM
    lionfoxx
    Is a themal expansion tank really needed?
    First home buyer, and Ever since I can remember we had well water, I do now as well in this new house. I was told by the local HomeDepot when I bought my tank, the installer was there and said if I have someone to do it, that there were new codes, had to have a lever ball valve shut off now, and for a closed system, meaning well water or newer homes with backflush valves to the city supply they require a themal expansion tank?

    I have asked my dad, my gf's dad, who both have tons of experience with installing H2O heaters and neither said they heard of it being a new code? My gf's dad has some rentals and has had some plumbers install his stuff and they never brought it up.

    Is what I am being told sales propaganda? I read about in the Water heater manal, but doesn't say it's a code, just recommended, and gives the reason why you may want to have it. I live in Ohio, how can I find out for sure?

    If the little 2 gallon thermal tank fills up, won't it still back flush beyond that? The diagrams I see for installing them show it before the main cold going to hot water tank, I have a cold tie in and a hot tie in right above the tank running to other side of house, so it would be impossible to put it after that, there would be no room, I would have to put it before that, which would cause hot water to back flush to the those lines even if I had a thermal tank installed?

    Is this really needed?
  • Feb 24, 2005, 11:05 AM
    labman
    Sounds like a bunch of over kill to me. The hot water heater still has a pressure relief valve. See what Tom has to say. Unless he gives a good explanation why you need it, I would put the system together without it, and demand that any inspector that doesn't like it, shows you where code requires it if you aren't on city water or sewage. If you are connected to the city sewage, you may have to do things their way. It may be easier to anyhow.

    ''a lever ball valve shut off '' Does that mean just an ordinary ball valve as a shutoff? If so, I would use ball valves for it and all my shut off valves except maybe for chromed angle stops in exposed places. Ball valves cost about the same as gate or globe valves. They shut off tighter, leak less around the stem, are more quick to use, and you can tell instantly whether they are open or closed. Any plumber installing gate valves is 25 years behind the times. Maybe that is why they want expansion tanks. If you shut off the supply to a hot water heater with a ball valve, it is really shut off and won't let any water back flow.
  • Feb 24, 2005, 11:59 AM
    speedball1
    Quote:

    Originally Posted by lionfoxx
    First home buyer, and Ever since I can remember we had well water, I do now as well in this new house. I was told by the local HomeDepot when I bought my tank, the installer was there and said if I have someone to do it, that there were new codes, had to have a lever ball valve shut off now, and for a closed system, meaning well water or newer homes with backflush valves to the city supply they require a themal expansion tank?

    I have asked my dad, my gf's dad, who both have tons of experience with installing H2O heaters and neither said they heard of it being a new code? My gf's dad has some rentals and has had some plumbers install his stuff and they never brought it up.

    Is what I am being told sales propaganda? I read about in the Water heater manal, but doesn't say its a code, just recommended, and gives the reason why you may want to have it. I live in ohio, how can I find out for sure?

    If the little 2 gallon thermal tank fills up, won't it still back flush beyond that? the diagrams I see for installing them show it before the main cold going to hot water tank, I have a cold tie in and a hot tie in right above the tank running to other side of house, so it would be impossible to put it after that, there would be no room, I would have to put it before that, which would cause hot water to back flush to the those lines even if I had a thermal tank installed?

    Is this really needed?

    I need you to Quote from the hot water heater manual why a "themal expansion tank" is needed ? Back flush? What's to back flush? How does one occur? And does "homes with backflush valves to the city supply" translate to homes with backflow preventers?
    And for that matter does backflush valves = backflow preventers?
    I can see no value on a "themal expansion tank", That's the function of the temperature and pressure relief valve.
    Call your local building department and ask if you wish but if it were me, and since a water heater replacement doesn't need a permit or to be inspected, I'd install my water heater the regular way. Regards, Tom
  • Feb 24, 2005, 01:38 PM
    lionfoxx
    Thanks,
    Yeah I guess backflush and back flow preventive are the same. In the manual they explain it better, stating that a well system is closed and a city water system is open, so if they h2o tank over boils and the relief valve fails it will pump hot water back through the cold water line. In a well system it can blow pipes, etc. in a city system it disipates out down the line, but I been told that new homes have a back flow preventive so you can even get any backflow into the city water system, which make sense to me, I thought it odd that anyone would have the ability to pump something back into a treated water line, but I guess it happens.

    Either way, I was told that Ohio, PA, and surrounding states are making their codes based off the h2o companies recommend installations. The installer guy said too many plumbers, stores and companies been sued when a tank overboils and the valve doesn't release, so they are covering their butts by having the thermal expansion tank recommendation in the manual, so installers and pluming codes are changing to include them.

    To me this is an over kill, the valve is suppose to work and it looks like someone is trying to put up an excuse for poor quality valves. My dad knew about thermal expansion tanks, but never heard any of this or seen it in a manual. The tank I bought is a GE 12 yr 40 gallonand it covers all this in the manual. Back when I worked as sears, all I ever seen them do for warranty replacement is to have the customer pull the tag off with the date and they would get a replacement based on the warranty and the date sticker. So this is all new to me as well.

    I think I am going to just put it in ourselves and live with it. My dad and my girlfriends dad between them have done about dozen and never heard of this, except for one time my dad did say he had a tank that overboilded and the valve didn't blow, and it warmed the water in the cold holding tank, but it was a bad h20 heater and he replaced it and never since then has he had an issue.

    I was mainly interested in others feedback or if they heard of this or not.

    Thanks, For all comments.
  • Feb 24, 2005, 03:38 PM
    speedball1
    Is a themal expansion tank really needed?
    "The installer guy said too many plumbers, stores and companies been sued when a tank overboils and the valve doesnt release, so they are covering their butts by having the thermal expansion tank recommendation in the manual, so installers and pluming codes are changing to include them."

    HORSE HOCKY!! BS! And hype! This "installer guy" couldn't have been a licensed plumber. My bet is that he worked for Home Depot. In my over 50 years out in the field I have never had a T&P valve fail. Never had a water heater back up steam in the cold water line and never had one blow up. Or ever heard of one in my area, (Tampa Bay). Once when I was a young boy I remember my father talking about a water heater blowing up but this tank didn't have a T&P safety valve installed. That was just about 70 years ago. Labman called it "overkill" I call it "a unnecessary expense scam". Regards, Tom
  • Feb 24, 2005, 10:12 PM
    tommytman
    +1 on that
  • Feb 25, 2005, 08:03 AM
    lionfoxx
    I agree, just a scam for extra money.
  • Feb 25, 2005, 08:31 AM
    labman
    I can remember some houses blowing up from the hot water heater. That was before all the gas controls. It was not the hot water, but gas when the pilot light failed.

    Water expands in the hot water heater as it heats. Normally a small amount is forced back the supply line. That is why you should never leave the hot heater heating with the supply shut off. If you have a back flow preventer, that is exactly what you are doing. Cold water flows in to keep the tank full. As it heats, the increased volume of water has to go somewhere. If the black flow preventer is before the pressure tank, it can flow back into it. I don't see the need for the backflow preventer. If you have one, you must have somewhere for the water to go. We are not talking a large volume, but unlimited pressure if forced into a fixed volume. The more I think about this, the more I am afraid it is something we have to live with.

    Vendors don't need many problems to convince bureaucrats to require this, that, and something else. The frivolous lawsuits don't help either. On further thought, this sounds like the lead in paint and asbestos scams that are costing the public millions. Excuse the political tone.
  • Mar 1, 2005, 04:32 AM
    apollo1
    Thermal expansion tank
    Here's my experience with a thermal expansion tank... I have an older home with city water that I recently replumbed. I replaced the regulator and the check valve (so water can't go back to the city line If they had a loss of pressure). The check valve was required by the water authotity. After that every time the gas hot water tank kicked on the pressure relief valve would let loose spewing water onto the floor... hot water tank was just replaced within 2 months due to a leak so the pressure relief valve was operating correctly.

    After some research,I installed a thermal expansion tank on cold water line to hot water tank and problem was solved. Water was expanding when heated with no place to go in the closed loop system with only the pressure relief valve to release the pressure... Sure that's its job but who wants water all over the floor all the time.
  • Mar 23, 2005, 07:19 AM
    speedball1
    Got to Eat My Words
    Quote:

    Originally Posted by speedball1
    "The installer guy said too many plumbers, stores and companies been sued when a tank overboils and the valve doesnt release, so they are covering their butts by having the thermal expansion tank recommendation in the manual, so installers and pluming codes are changing to include them."

    HORSE HOCKY!!! BS!! and hype!! This "installer guy" couldn't have been a licensed plumber. My bet is that he worked for Home Depot. In my over 50 years out in the field I have never had a T&P valve fail. Never had a water heater back up steam in the cold water line and never had one blow up. Or ever heard of one in my area, (Tampa Bay). Once when I was a young boy I remember my father talking about a water heater blowing up but this tank didn't have a T&P safety valve installed. That was just about 70 years ago. Labman called it "overkill" I call it "a unnecessary expense scam". Regards, Tom


    Some time ago I wrote this post calling hot water heater expansion tanks a " unnecessary expense" I WAS WRONG. Expansion tanks ARE needed when a water service has a check valve or a backflow preventer installed. In my defense, I retired in 1988 before backflow preventers became code in my area. Back then the added pressure caused by expanding heated water had a place to vent. With the advent of check valves and BFP's the pressure had no place to vent but out the T & P valve on the heater. I apologize to the readers of this site and to my fellow experts for my ignorance. With the assistance of my code book, a library of reference books that I've collected over the years, plus the plumbing training at my fathers shop in the 40's and the experience gathered over the years in all phases of plumbing, I have attempted to share some of that experience with the askers on this and a few other sites. If my answer about expansion tank has caused and confusion or expense then I am truly sorry. Please consider this a blanket apoligy. Tom aka speedball1
  • Mar 23, 2005, 08:25 AM
    labman
    Yeah, my last answer was 180 degrees from my first one too. It can be very difficult to see all the consequents of something new. And the longer you have been around, and the more you know, the harder.

    Story about the kid that came out of trade school and applied for a job with a master carpenter. The carpenter asked the kid if he ever made a mistake. The kid said ''No, never!''. The carpenter said, ''Well I can't have anybody working for me that hasn't learned to fix mistakes.'' The first step is to admit you made a mistake. Best we can hope for of anybody is to seldom make mistakes, but see them and fix them when they do. Now about Shooter's square nut that won't turn.
  • Mar 23, 2005, 09:16 PM
    tommytman
    Speedball. Don't beat yourself up over this. As far as I'm concerned if the house is built with a check valve it should already have the expansion tank. I don't have a check valve so I'm not going to run out and buy an expansion tank.
    Tom
  • Aug 6, 2008, 08:47 AM
    Not-A-Plumber
    Well, I'll be honest with you, I think in some cases this is a scam. Here's my situation.

    I live in Concord, North Carolina. My house was built in 90-91 time frame. This past weekend my natural gas water heater failed. Specifically, it leaked. Now, this is the original water heater that was installed back in 91 and it had no expansion tank installed with it. So my plan was to try and replace the water heater myself. I bought a 50 gallon water heater with a 12 year manufacturer warranty. I get home and soon discover during the installation that the gas line doesn't even come close to lining up with the control box on the new water heater. Not being experienced with plumbing for natural gas I decide to get a professional. I also decide that I'll have him hook up the water lines as I'm having absolutely no luck getting them not to leak.

    I call and talk to a plumber today. I explain to him what I need done and ask him what kind of damage I can expect on my wallet. He asks me if I already have a thermal expansion tank. I had an idea of what he was talking about as I had seen this referenced in the owner's manual. I told him that I didn't because the old water heater didn't have one installed. He then tells me that I will have to have one installed at the tune of $275. Of course I had to pick myself up off the floor because I had just spent $450 on a new water heater. I asked why I needed this when the old water heater didn't have one. He then tells me that it's code. In fact it's state law. At this point I'm beginning to feel like maybe I need to hook myself up to a thermal expansion tank because I'm fuming. :mad:

    So I'm left asking myself... why the hell do I have to have this when it wasn't there before? Nothing has changed in regards to my connection (at the curb) to the city water line. Obviously nothing has changed in regards to the plumbing in my house.

    Unfortunately, I don't think I have a choice. You see, here in Concord, replacing a water heater requires a permit upon which I have to have it inspected once the installation is complete. If I did decide to try and perform the water hookups myself without installing the thermal expansion tank, my hunch is that it won't pass inspection.

    This is the ever classic damned if you do, damned if you don't situation. :mad: I'm sorry but, like one of the previous posts mentioned, I'm of the notion this code/state law is politically motivated. It seems to me that homes of a certain age should be grandfathered from having to comply with something that's not needed rather than making a blanket enforcement.

    I'm sure this was lobbied for in a major way. Think about it, if these tanks really do have such a short life span then suddenly you have a whole new demand for these and manufactures will be pumping these out of China like crazy. Plumbers then have a new revenue stream with significant price mark up and a nice fat hourly installation rate.

    I'm off to Lowe's to see if installing this is something I can do myself. I can only hope so as it would save me around $250.
  • Aug 7, 2008, 04:25 AM
    speedball1
    If you decide on purchasing a expansion tank we can walk you through the installation if you wish. It's a simple procedure.
    Quote:

    I'm left asking myself... why the hell do I have to have this when it wasn't there before? Nothing has changed in regards to my connection (at the curb) to the city water line. Obviously nothing has changed in regards to the plumbing in my house.
    I'm with you. On this. There's absolutely no reason to install a expansion tank unles you have a check valve or a backflow preventer installed.
    Thousands of homes in my area are without expansion tanks and they get along just fine. Good luck, Tom
  • Aug 7, 2008, 06:17 AM
    Milo Dolezal
    The Thermal Expension Tank sells for about $42.00. Is it needed ? Depends who you ask. We do install them - but mostly as precaution not as requirement. You be the judge...
  • Nov 10, 2008, 08:16 PM
    Hometec
    Hi,
    I'm a 59 year old licensed plumber in NC. I came across this site by accident and was appalled at some of the answers concerning expansion tanks. Please allow me to set forth some facts. :) Expansion tanks are required by the International Plumbing Code, which covers the USA, since 2000. In a closed system, the heated water expands and has to go somewhere. Either the t&p is going to open constantly, or pipes are going to burst. Water seeping from the t&p can corrode the valve causing it to fail. I recently watched videos of exploding water heaters that had sealed t&p valves. In each case the house was completely leveled, a large crater was created by the blast, and the tank soared 600 feet into the air. The explosion was equivalent to two pounds of dynamite. Google "exploding water heater" if you need more convincing. When a licensed plumber tells you that you need an expansion tank, he is simply abiding by the code and operating according to his knowledge to keep you safe. In our state, if he does not install an expansion tank, or does not pull a permit on the install, he is in violation of the plumbing code. There are severe consequences for such violations, including probation or loss of plumbing license.
    Thanks
  • Nov 10, 2008, 10:35 PM
    Milo Dolezal

    We don't install Expansion Tanks on new houses. I personally know of 1 (one) case where Expansion Tank was needed. That's 32 years of being in the trade. I think it is sales politics.

    BTW: Home Depot sales people know diddly nothing... Their main concern is to meet sales quota every week.
  • Nov 11, 2008, 06:31 AM
    speedball1
    Quote:

    In our state, if he does not install an expansion tank, or does not pull a permit on the install, he is in violation of the plumbing code.
    I think Hometech is overstating the danger. Pull a permit to change out a water heater? How about a faucet? Need a permit to install one of those? You guys must spend more time down at the Building Department pulling permits then you do out in the field running calls.
    Quote:

    Expansion tanks are required by the International Plumbing Code, which covers the USA, since 2000.
    SAY WHAT?? When were all theNations Codes trashed and replaced with IPC?
    Quote:

    In a closed system, the heated water expands and has to go somewhere. Either the t&p is going to open constantly, or pipes are going to burst.
    At last! Something we can agree on. The operatable word here is "CLOSED. Yes a closed system demands a expansion tank. But
    Quote:

    every water heater ins mandated to have a installed expansion tank.
    OVERKILL!! We have thousands on water heaters in my area without a expansion tank and they are doing just fine ,thank you.
    I think Hometec is running around shouting, "The sky is falling". Regards, Tom
  • Nov 11, 2008, 05:40 PM
    Hometec
    Quote:

    Originally Posted by speedball1 View Post
    I think Hometech is overstating the danger. Pull a permit to change out a water heater? How bout a faucet? Need a permit to install one of those? You guys must spend more time down at the Building Department pulling permits then you do out in the field running calls.
    SAY WHAT?? When were all theNations Codes trashed and replaced with IPC?
    At last!! Something we can agree on. The operatable word here is "CLOSED. Yes a closed system demands a expansion tank. But OVERKILL!! We have thousands on water heaters in my area without a expansion tank and they are doing just fine ,thank you.
    I think Hometec is running around shouting, "The sky is falling". Regards, Tom

    Hi Tom,
    In our state (NC) and many other jurisdictions the IPC was adopted in place of the UPC in 2000. All the municipality and county water systems that I work on MUST have expansion tanks. If I do not install an expansion tank—on the cold water side—I will be turned down by the plumbing inspector. Permits are mandated on all water heater installs. You are welcome to email the State Board of Examiners if you doubt my statements. [email protected]

    We are not required to pull permits on faucet installs. Yes, it is an aggravation to have to pull permits, but there are some plumbers in our area that wish they had done so. I think some of them are working in the plumbing department of Lowe's and Home Depot nowadays.

    There are thousands of water heaters in our area that are without expansion tanks, but they were installed before the new code took effect, or were installed illegally. The t&p’s on most of those water heaters are going to fail prematurely. Further, the excessive expansion and contraction of those water heaters is going to crack the glass lining, allowing the water to get to the metal. This will shorten the life of those heaters.

    More and more municipalities and counties are going to closed systems to protect the potable water supply. They are installing backflow preventers (check valves) at every meter. This is billed as an effort to prevent faulty water closets and other mishaps from contaminating the potable water. A couple of years ago, a man in Cary, NC hooked his travel trailer sewage tank to the potable water supply to flush it out. The entire water system of the city of Cary was shut down because of the contamination of the potable water supply.

    An additional danger is the lack of knowledge. I have come across several water heaters in closed systems where the t&p had been leaking because of expansion (something you agreed with). In two cases the homeowners had attempted to stop the leak by plugging the t&p. One of those water heaters had a stuck thermostat. It was literally shaking and the pipes on both the cold and hot water side were sweating profusely. As I stated in my last post, and the facts support my statement, an exploding water heater is equivalent to two pounds of exploding dynamite (just Google it). If you install a water heater, do not pull a permit, and damage occurs, good luck getting the State Board and the Insurance Company to let you slide because you did not believe the code was accurate or necessary.
    Thanks,
    C. H.
  • Nov 12, 2008, 08:19 AM
    speedball1
    Quote:

    In our state (NC) and many other jurisdictions the IPC was adopted in place of the UPC in 2000.
    Any code has just got to be better the UPC.
    Quote:

    You are welcome to email the State Board of Examiners if you doubt my statements.
    I don't doubt you, We all have code "overkill".
    Quote:

    Further, the excessive expansion and contraction of those water heaters is going to crack the glass lining, allowing the water to get to the metal. This will shorten the life of those heaters.
    The sky is falling!! Gee! I haven't seen any mass failure of water heaters in either my area or the entire West Coast of Florida. Must be your water huh?
    Quote:

    There are thousands of water heaters in our area that are without expansion tanks, but they were installed before the new code took effect, or were installed illegally. The t&p's on most of those water heaters are going to fail prematurely. Further, the excessive expansion and contraction of those water heaters is going to crack the glass lining, allowing the water to get to the metal. This will shorten the life of those heaters.
    And you know this for a fact, how?
    Quote:

    An additional danger is the lack of knowledge. I have come across several water heaters in closed systems where the t&p had been leaking because of expansion (something you agreed with). In two cases the homeowners had attempted to stop the leak by plugging the t&p. One of those water heaters had a stuck thermostat. It was literally shaking and the pipes on both the cold and hot water side were sweating profusely.
    It's just got to be something I n the water up there the robs homeowners of good sense. We don't seem to have that problem here.
    Quote:

    As I stated in my last post, and the facts support my statement, an exploding water heater is equivalent to two pounds of exploding dynamite
    I agree, back when I was a boy my father took me to see a heater that had exploded. It blew through two floors,the roof and landed a half a block away flat as a pancake. But 70 years ago was the last time I've rrun into it.
    Quote:

    If you install a water heater, do not pull a permit, and damage occurs, good luck getting the State Board and the Insurance Company to let you slide because you did not believe the code was accurate or necessary.
    Amd what are we supposed to tell the thousands of homeowners that have neither a closed system or a expansion tan k? RUN FOR THE HILLS! THE SKY IS FALLING
    Don't mind me, CH, (Charley, Chuck? Chance? ) I get real frisky first thing in the morning. I will agree that expansion tanks are a necessity when the system's closed but when the system's not closed the water has the service to expand out into.
    We don't experience the dire consequences of having our heaters blow up or fall apart due to contraction and expansion. Must be native to your area.
    You have given me all sorts of "hypothetical" situations
    . Let me give you one. Homeowner with a closed system and one of those bad T & P Valves you love to talk about. But that's OK because he has a expansion tank installed right? WRONG! Something's got to blow when the pressure exceeds the limit the expansipon tank will hold. RUN FOR THE HILLS MAGGIE! SHE'S ABOUT TO BLOW!! Just having a little fun with you CJ. Nothing personal. By the way. Welcome to the plumbing Page. Hope you stick around and contribute your expertise. Don't let me put you off. Everybody on here's nicer then me! We have some good plumbers here . I hoe you decide to become one of us. Regards and welcome, Tom
  • Nov 12, 2008, 10:17 AM
    jlisenbe

    In the case of an expansion tank, will it simply fill with water after years of use once the air inside gets dissolved into the water, much like what happens in the pipes intended to prevent water hammer?

    Just a question.
  • Nov 12, 2008, 10:27 AM
    Hometec
    Quote:

    Gee! I haven't seen any mass failure of water heaters in either my area or the entire West Coast of Florida. Must be your water huh?
    Hi Tom,
    I am glad that there have been no water heater problems in your area, and hope that there are never any. However, when the water heater exploded in an Oklahoma school, killing a teacher and six students, the sky indeed had fallen for the loved ones and survivors. Please realize that the code is not established on how many things go right, but on what has and could go wrong. What could go wrong is that some jack-leg repairman, or a homeowner with a lack of common sense, could plug the leaking t&p. That type of ignorance of water heaters cannot be attributed to the water here in NC, but probably comes from drinking water from non-closed systems. :) The fact is a water heater has the potential to explode. Everything that a plumber can do to comply with the code should be done to limit that potential.

    If you don’t put an expansion tank on a CLOSED SYSTEM, and a water heater explodes for what ever reason, you’re going to be the whipping boy. The Insurance Company is going to subrogate against you and the State Board will take your plumbing license. If people are killed, you will be blamed by the friends and relatives and you may as well move out of the state. Further, it will make no difference what you believed before it exploded, you will carry the doubt and guilt for the rest of your life.

    Now, you keep bringing up NON-ClOSED SYSTEMS, which I have not elaborated on. The reason that our code requires expansion tanks on non-closed systems is because they are not going to stay that way long.

    Expansion tanks might not prevent water heaters from exploding that have frozen t&p’s, but they buffer the thermal expansion on the closed system, The water heater itself expands and contracts, and that this process is what cracks the glass lining and allows the water to deteriorate the metal. Therefore, it is a given that an expansion tank can buffer the thermal expansion.

    Quote:

    And you know this for a fact, how?
    It's just got to be something I n the water up there the robs homeowners of good sense. We don't seem to have that problem here.
    The following is comes directly from the A. O. Smith Corporation, the largest w/h manufacturer in the USA.
    Quote:

    Thermal Expansion as relates to water heaters/boilers is an increase of the volume (or space taken up) by water within the unit, caused by heat. In other words, when water heats it expands or takes up more space. The excess volume of water, because of pressure created, will flow to the place of least resistance. Unless a faucet is open, generally this would be into the cold water pipe (this is why sometimes the pipe above the cold water inlet is warm for a few feet). In a closed system, the excess volume of water has no place to go and builds pressure within the unit. When the pressure reaches a certain point, a safety device called a temperature and pressure relief valve (T & P) will open relieving pressure. Over time (perhaps as little as months or as great as years) this increase and decrease in pressure, without the protection of an expansion tank, can weaken the tank causing premature failure. Generally what is seen is a drip to a stream of water from the T & P that continues until pressure is relieved. Most often reported is a cup to a few quarts of water a day - to every few days. And, usually the release of water is greater after a large amount of hot water has been used - like taking a shower. These symptoms may be evident immediately upon installation or months to years down the road, or even not at all until the water heater fails.
    I take no offense at your remarks, Tom. My skin has thickened over the years of dealing with the public and very persnickety plumbing inspectors. However, I hope that you see the benefits of expansion tanks on non-closed systems since they are likely to become closed.
    C. H.
  • Nov 12, 2008, 10:29 AM
    speedball1
    Quote:

    Originally Posted by jlisenbe View Post
    In the case of an expansion tank, will it simply fill with water after years of use once the air inside gets dissolved into the water, much like what happens in the pipes intended to prevent water hammer?

    Just a question.

    And when the expansion tank loads up with condensate it's the same as if there were no tank there at all. Regards, tom
  • Nov 12, 2008, 10:42 AM
    Hometec
    Quote:

    Originally Posted by jlisenbe View Post
    In the case of an expansion tank, will it simply fill with water after years of use once the air inside gets dissolved into the water, much like what happens in the pipes intended to prevent water hammer?

    Just a question.

    Hi jlisenbe,
    I confess that I don’t know about air being dissolved into water, but expansion tanks do fail. The primary reason that they fail or fill with water is the air bladder or Strader valve develops a leak. Of course, the tank can also develop a water leak. Air dissolved in water contains approximately 35.6% oxygen compared to 21% in air, so it may not be an issue. However, I believe that water has to boil before air dissolves in water, and that should not occur inside of the expansion tank if it is installed on the correct side, the cold water source. I have seen expansion tanks on well systems that were so old the manufacturer was no longer around, but they were still working. However, I heard that there were some bad problems with expansion tanks in Myrtle Beach, SC. Those problems were due to poor manufacturing. Hope that helps.
    C.H.
  • Nov 12, 2008, 11:06 AM
    speedball1
    Quote:

    I hope that you see the benefits of expansion tanks on non-closed systems since they are likely to become closed.
    I believe what I'm fixing on is
    Quote:

    on non-closed systems since they are likely to become closed
    . That's quite a assumption, how did you arrive at it?
    I agree that a expansion tank's necessary when the system's a close onr. But to charge a customer for a installation based on a maybe you'll install a sprinkler and be forced to install a backflow preventer Down here we don't install a appliance or a fixture based on a "MAYBE. Cheers, Tom
  • Nov 12, 2008, 03:48 PM
    Hometec
    [quote] That's quite a assumption, how did you arrive at it?[quote]

    As I previously stated, but I don’t mind reiterating, the code requires expansion tanks on all water heater installs in our state. Closed systems, we agree on. Expansion tanks should be installed on non-closed systems because the code requires it. The reason is because there is a massive effort to make all potable water systems closed. The premise of this effort may be because of the contamination factor from home. However, another reason may be Homeland Security. Instead of a million places where a terrorist can hook a hose to the potable water and send anthrax throughout the neighborhood, maybe they narrow it down to a few access points by installing check valves everywhere. It doesn’t really matter why when the code requires it. The only choice then is if you intend to comply with the code. BTW, I do not charge labor for installing expansion tanks. My w/h install labor price is the same as it was before expansion tanks were required. The motive is not money, but code compliance.
    Thanks,
    C.H.
  • Nov 12, 2008, 04:25 PM
    jlisenbe

    HT, I am more familiar with wells. The air in a pressure tank (non-bladder) will dissolve into the water (due, I suppose, to being under pressure) within a few months, and we are talking about a fifty or sixty gallon tank. However, you mentioned that these expansion tanks have a bladder in them, so that would answer my question.

    As usual, I am enjoying this exchange. It brings out a lot of truth when these experienced guys debate these issues.
  • Nov 12, 2008, 04:42 PM
    speedball1
    Thank you Hometec for your explanation. I completely understand your reasoning.
    Quote:

    The reason is because there is a massive effort to make all potable water systems closed.
    And will this "massive effort" be retroactive? Because it hasn't got here yet, ( we're still waiting) How can I word this? I have had experts on this page who were dtickers for code. if it don't agree with my code it ain't right!! Our answers don't always follow code. We are more about getting the asker repaired This is not to say we promote dangerous plumbing practice. It means if we have a asker with a 100 year old house with "S" traps throughout with a drainage leak we don't attempt to force him to upgrade his drainage to vents and "P" traps. We tell him how to fix his leak. That's what this page is all about. The asker is king and our goal is to get his problem fixed the fastest easiest and cheapest way that he can do himself. Of course when we lay out a plan we follow code but when we answer we kind of tiptoe around it. I don't want to hear, "This is't code in my area". I want to hear, "this is how to repair your problem". Regards, Tom
  • Nov 12, 2008, 05:29 PM
    Hometec
    Quote:

    I don't want to hear, "This is't code in my area". I want to hear, "this is how to repair your problem". Regards, Tom
    Hi Tom,
    I apologize for misunderstanding your intention with this site. I read disparaging remarks about licensed plumbers installing expansions tanks as if they were attempting to bilk the public , etc. I can understand your information about s-traps, faucets, and the like coming from the perspective of helping a homeowner with plumbing repair. No one ever died from an exploding faucet or siphoning s-trap. However, when you tell someone to do something that could cost them their lives…maybe you ought to explain the danger as well. I apologize if my posts offended you. Lots of luck with your site.
    C. H.
  • Nov 29, 2011, 06:23 PM
    spudwrench
    I have been a plumber for thirty years. For the record the higher the water pressure you have in your house the more problems you will have with your plumbing. It is always looking for the weak links in your system. I always had more service calls in the parts of town with higher pressure. If you have a check valve in your meter at the curb, you will have too high of pressure in your house. You will need a expansion tank to prevent your pressure from climbing. It is for protecting the whole plumbing system. Not just the t&p valve from opening. High blood pressure may not be what kills you one day but if you want to play the odds you take care of it. For the plumber that never saw a t&p fail, well I have been to three service calls were the water exploded. I don't think these so called plumbers care that they install waters heater wrong and leave your house with 130 psi on your weak plastic ice maker line.
  • Nov 29, 2011, 06:33 PM
    massplumber2008
    Hi Spudwrench

    Nice post, but look at the dates of this thread and you'll see that it is back from 2008. Always check dates before posting, OK (and make sure the question hasn't already been properly answered)?

    I hate to see anyone write that much and have it go unappreciated! :)

    Have a great day!

    Mark
  • Mar 10, 2013, 06:48 AM
    TomFMB
    I am on city water. The city does NOT have check valves at meter and I do not have a check valve either. The Thermal Expansion Tank is releasing water back out... then brings it back in when pressure drops below city pressure. Consequently I am paying for the same gallon of water over and over. We isolated this, with a licensed plumber, to the Thermal Exp Tank. There is a T&P in place as well and drains into a try if needed and out of the house. Electric water heater. I am planning on putting in a check valve, but city pressure is not all that great to begin with and I have been told anywhere from 6-10 psi drop. Would you add check valve or remove thermal tank? Thanks
  • Mar 10, 2013, 07:53 AM
    massplumber2008
    Hi Tom...

    I would remove the expansion tank to start and watch the little red dial on the meter. I seriously doubt the issue is with the expansion tank and suspect that you have a leaking hot wtaer pipe. Check out the answer I posted at the question you posted at the main plumbing page and leave your answer or any questions back at that thread. Thanks...

    Mark

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