Opinion on expansion tank installation. Picture included.

Discussion in 'Water Heater Forum, Tanks' started by John Vega, May 23, 2011.

  1. ballvalve

    ballvalve General Engineering Contractor

    Messages:
    3,261
    Location:
    northfork, california
    Certainly expansion tanks work and reduce pressure flucuations - until they fail, and that is a definite. And homeowners dont give a whit about checking them while trying to keep up with all the other more obvious failures in life like a flat tire.

    A large percentage of homes in america do not have city supplies, and many that do, dont have a regulator. So before installing the bag in a can with no visible failure indicator, the plumber should evaluate the supply system. [many do not because they want that extra 200 bucks on the job]

    A sys with the ex tank, which holds pressure to lets say 70..... then a 100 psi relief valve... then the final solution the valve on the WH. Now you know when the ex tank has failed, if your 100 psi, 7$ valve drips.

    I do not advocate the watts ballcock. Seems a bit stupid. However, the screw on relief valve for a hose bib [the drain valve?] is interesting.

    The watts ballvalve-relief valve combo should be standard practice, set above the max accumulation of the ex. tank.

    The point about all toilet valves being relief valves is that the cheap plastic will blow at high pressure, long before the water heater tank.

    Why install a 10 or 15 year waterheater and 5 or 7 year ex tank? Give your customer a failure indicator.

    This has nothing to do with 'engineering' but all to do with common sense.
  2. Redwood

    Redwood Master Plumber

    Messages:
    7,450
    Location:
    Connecticut
    You are absolutely correct! Most things do work until they fail! You're thinking expansion tanks fail far more often than they actually do. Properly installed and sized they have a long service life. In my own home I have an expansion tank on the boiler and water heater and am in my mid 50's. I can count the replacements of both on less than 1 hand...

    The visible sign of failure for a thermal expansion tank is the T&P valve leaking a small amount of water. There is no visible sign of failure on a relief valve until you receive an enormous water bill for dumping water down the drain.

    A plumber should always troubleshoot the system to determine if an expansion tank is needed as well as other causes for a T&P discharge.

    Except you will not see the valve dripping as they are plumbed to a drain. Also your $7 valve is actually much closer to $50 or, more....

    You did advocate it in the past. Your relief valve that screws onto a hose bibb or, drain valve is not useable for the same reason as the ballcock... It can be isolated by a valve and kept from affording protection to the water heater.

    I agree to disagree with you on this subject.

    If you want that in your home that is just hunky freakin dunky... Put it in! But I would not advocate that for a majority of sensible people it is a redundancy that is not needed.

    Maybe... Maybe not... Did you engineer it?

    Again, your figures of failure on expansion tanks are vastly overrated...
    If you are experiencing expansion tank failures at this high a rate you should either learn what you are doing wrong on the installation. Or, stop hiring CraigsList Plumbers... Clearly something isn't right!

    Again the relief valve has no visible sign of failure, but the expansion tank failure will result in a small t&p valve discharge.

    I agree! When are you going to get some?

    mud_wrestling.jpg
    Last edited: May 29, 2011
  3. What is a thermal expansion tank cost installed??

    yes, their is a possiblilty that a thermal expansion tank
    may extend the life of a water heater, a year or two...

    that is if it does not become waterlogged in 6 years or less.. and someone checks the pressure levels in them every year or so......(not gonna happen)

    we do offer them when we install a heater, but on average most everyone does not care to spend the extra money for a variety of different reasons.

    the larger thermal tank is worth about 60 bucks, ....what does everyone think is a fair price to install one while doing the installation??

    I offer them installed for $150....
    and another 250 for a prv valve....

    and their are places in town that attempt
    to get about $600 for both...:confused:

    we are getting on average about 10 years out of Rheem gas heaters in this area without the help of thermal tanks....with averge pressure rangeing around 80psi....

    very few people actually drain or clean out their heaters, and less that that number will ever check the pressure on thermal tank

    so....after about 9 years, with the lime buildup and sediment buildup inside the heaters.....the efficinecy of the heaters starts crashing...

    at what dollar amount does it all become a mute point???


    so what do people charge to install one at time of installation??



    come on....lets figure this out
    [​IMG]



    Redwood...I wish I were an einstein and could make up some fancy graphs
    showing some wiggley lines on it with the cost of the thermal tanks
    vs.. the drop of co-efficiency of the water heater after 10 years,,,
    divided by the ......mass of the ass of your old lady......
    taking showers every day.......

    then we could finaly get this questioin answered....
    Last edited: May 30, 2011
  4. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,230
    Location:
    Cave Creek, Arizona
    quote; in theory, as long as they still work. When I took out my 10 year old tank, I tried releasing the TPR to break the vacuum and it was seized shut

    And I suppose you had NOT tested it during those 10 years. THAT is the reason it is recommended that WE test the T&P valves on our customer's water heaters whenever we are in the building. They may not like it when it proves defective by either NOT opening, or not closing when the lever is released, but it will prevent a situation such as a "10 year old heater with a frozen T&P valve".
  5. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,230
    Location:
    Cave Creek, Arizona
    quote; BUT, exactly for that reason that water could get pushed back into the supply from a house, and it could have gotten polluted in the house,

    Just as the expansion tank only has to absorb a SMALL amount of water to eliminate thermal expansion pressure, the amount of "backflow" would be in the range of a few inches, and NO WHERE near enough to force "water from the house" back into the city main. The ONLY water which would be pushed back into the main would have been between the main and water meter and would NEVER even have been near the house.
  6. SteveW

    SteveW DIY Senior Member

    Messages:
    1,053
    Location:
    Omaha, NE
    We have gotten too...something -- not sure what the right word it -

    ...lazy?

    ...reliant on automatic systems to keep us safe?

    ...complacent?


    We don't check our car tire pressures any more so now we have federally mandated automatic pressure checking systems. Last time I had a flat fixed, they charged me double because the tire in question had one of those radio transmitters to tell the computer what my tire's PSI was.

    I for one (and I know I'm pretty rare in this) check my TPR valves about once a month, and I bang on both ends of my thermal expansion tank about once a month to make sure it's not waterlogged. I check the pressure about once a year.

    Now some smart plumber/entrepreneur needs to apply the car tire pressure monitoring system to checking expansion tank pressure! Make a million bucks.
  7. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,183
    Location:
    NW Ontario, Canada
    Checking the pressure without depressurizing the water line is a waste of time as the air pressure should be the same as the water pressure. Every time you check the air pressure you let a small amount of air escape and will eventually have to add more air. An automatic system would have to be quite sophisticated to be able to discern how much air by volume, not PSI is in the tank.
  8. ballvalve

    ballvalve General Engineering Contractor

    Messages:
    3,261
    Location:
    northfork, california
    The flaw here is that the TP valve leaks only at 150 psi, way beyond where your system pressure should EVER go. Second flaw is that without a lower value valve or tank, you will likely see pressure top off around 80 or 100 or 120, depending on how much pipe is in the house and how flexible it is. Or how often someone uses water and what temperature its set at. So one likely never sees that pressure flucuation.

    I have a closed sys at a rental without a ex tank, and I notice pressure tops at 80 when it sits for along time. Its electric with maybe 130' water.
    Which likely explains how the world survived so long without them.

    As to exploding toilet valves, send it to myth busters for a try. Or hook one up to your nitrogen tank.

    When one builds a airlliner like a water heater or a submarine, without riveted aluminum sheets, then we wont end up with convertible 737's.

    And when one teaches the Airbus pilots a bit of common sense that a kid learns with a battery airplane, they will put the nose down to gain speed, not up to guarantee disaster. Their altitude indicator worked, so WTF was with these clowns? The french factor? Airbus is VERY sad that the boxes were found!

    Finally, interesting how plumbers sit by and allow Stalin to make them ruin the cost of housing and kill building by forcing sprinklers on us. [More pipe=more money$$$$] And those idiotic backflow valves. And politically foist expansion tanks on us even in systems that dont need them.

    If our legislators had any sense, and plumbers had a lobby, sprinklers would be in the kitchen and utility room only. And a water heater would have a 100 psi back up relief valve.

    Now there would be more houses to build and we would all make more money.

    The codes are making a lot of "criminals" around here - cannot afford a permit- build without it - or rather buy a OSB mobile box and let it rot out in 20 years - the American way.
    Last edited: May 30, 2011
  9. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,183
    Location:
    NW Ontario, Canada
    I don't test it because I don't have a replacement standing by should it fail to reclose. Yes, a tech should test it and a tech should have a spare in his/her truck. Since I have a rental, I would not incur the cost to replace a unit that failed while testing.
  10. Redwood

    Redwood Master Plumber

    Messages:
    7,450
    Location:
    Connecticut
    The only flaw here BallValve is your Logic! Badly Flawed!

    How many times would a T&P discharge before it is noticed?
    VS.
    The thousands of pressure cycles to the relief valve set point that would provide no indication to the homeowner.

    One has a visible indicator and the other has none! Don't you get it?

    Well here is one instance where the Toilet Valve didn't explode under pressure.
    Something else did though....

    [​IMG]

    Yes, of course welds are exempt from metal fatigue...
    Say is that a crack pipe hanging offa your lip?

    [​IMG]

    A Submarine hull will never fail! They are welded of course...

    [​IMG]

    The Mud Wrestling goes on....

    [​IMG]
  11. good luck with it


    I know better than to open the t+p valve.. in a customers home without asking first....

    becasue 99% of the time It will always leak and someone is going to have to change that valve to keep if from pissing all over the place ....

    That is pretty close to sabatoge and the customer is never pleased to shell out $$ for something that was working just fine before you touched it with your boney fingers.......

    if they give you permission to check it and want it inspected for safety then that is one thing....

    I dont think that anyone would pay for a maintaince contract to have
    the t+p valve and thermal tank inspected every year..., perhaps I am wrong...

    .:cool:


    [​IMG] Look that this limed up valve, if you touch that one
    I guarantee you will be changeing it out... I would give them a replacement
    price before I ever laid hands on it...
    .
    Last edited: May 30, 2011
  12. Neanderthal Man

    Neanderthal Man The Cave Man

    Messages:
    11
    Location:
    In a Cave
    Come on Bro simmer down.
    You know we weren't raised around indoor plumbing.
    Lets just figure out how we can get that mound of crap in the toilet to go away and not raise a ruckus.
    Ever since that damn Geico commercial made us all that money we've had so much trouble figuring out how all this stuff works.
    We should have just stayed in the cave.
    At least then we could just crap in the woods.
    I know there has to be an easy way to empty the toilet out.
    Everything else turned out to be easy once we learned how.
  13. Redwood

    Redwood Master Plumber

    Messages:
    7,450
    Location:
    Connecticut
    Try pushing the chrome lever on the upper left side of the toilet tank.....
    Depending on how much stuff is in the bowl it may overflow.
    Be careful and you might need a plumber.
  14. Jerome2877

    Jerome2877 In the Trades

    Messages:
    397
    Location:
    BC
    Electrical fires can happen anywhere in the home, people smoke and light candles in other rooms as well. Now your really showing your ignorance! Besides if you go to the trouble of installing sprinklers in your home why wouldn't you protect the entire home, the cost savings would be pretty irelovent when a family member died because you wanted to save a few bucks!
  15. Redwood

    Redwood Master Plumber

    Messages:
    7,450
    Location:
    Connecticut
    Sounds like you were just born in the wrong country BallValve....

    [​IMG]

    Most of us just don't want to live in your vision....
  16. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,230
    Location:
    Cave Creek, Arizona
    quote; A Submarine hull will never fail!

    I assume that picture was of the Thresher, a victim of "freezing water". If you have a fire in your bedroom, because you were smoking in bed, you will be VERY happy that you were required to have sprinklers in the house. Getting the "stuff" out of the toilet bowl is so easy, "Even a caveman can do it". You sound like you want to go out in the woods and join up with the Survivalists.
    Last edited: May 31, 2011
  17. everything will fail eventually.....

    wether it be a submarine, water heater, or thermal expansion tank
    ... some day it will fail....

    the problem here is the astronomical odds and stats ....

    its nice to have everyone all safe and cosey... but when you look at the odds of something bad happenning....

    the odds of a water heater blowing up is probably once every two or three years...in a country of over 210 million poeple

    YES it does happen, but your odds are better for you to
    hit the power-ball lottery than to have one ever blow up on you

    the odds that I have two of them in my front window that blew up is astronomical

    basically what I am saying is the things are pretty damn safe.
    and they have been safe for decades.....
    without the thermal tanks on them.

    as far as making fire sprinklers a law for all homes, to save a few lives
    that aint ever gonna happen.....:cool:

    [​IMG]
  18. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,313
    Location:
    New England
    Nobody ever said an expansion tank would prevent a WH from blowing up! That isn't its purpose. It is to prevent stress fractures and (primarily) maintain constant pressure in the water system.

    There are some places where sprinklers are required on new construction. Expect to see it spread. What you spend on installation will normally be saved on the insurance for the house. As with most codes, existing homes are grandfathered.
  19. Redwood

    Redwood Master Plumber

    Messages:
    7,450
    Location:
    Connecticut
    It was either the USS Thresher SSN-593 or, the USS Scorpion SSN-589 I'm not sure...

    Maybe our esteemed General Engineering Contractor can tell us what went wrong on the USS Scorpion....
    He seems to know a whole lot of nothing about everything else.....
  20. Redwood

    Redwood Master Plumber

    Messages:
    7,450
    Location:
    Connecticut
    Master Mark is missing the boat on the Metal Fatigue and Stress Cracking...
    He's not understanding the comment to Ballvalve about the water heater exploding before the ballcock did...

    It's too bad he doesn't know the Residential Fire Sprinklers are already in the 2009 IPC so next code update he'll be a dinosaur.....
    Even Water Conditioner Installations have to be considered as part of the Residential Sprinkler Code....

    That will never Happen....:rolleyes: Or did it already?
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