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  1. #1
    Join Date
    Sep 2009
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    13

    Questions before getting a new water heater

    A friend's 16 year-old gas water heater started to leak a few days ago. The water has corroded through the outside shell. Fortunately it's a slow leak.

    The water heater stands on the floor and has no pipe connected to the pressure relief valve. There is no pan under it.

    Would the hvac contractor want to add a pipe from the pressure relief valve to the outside? The water heater is in the middle of a finished basement and the overflow pipe would have to go through two walls in living space to get to the outside. It would be pretty ugly. Can the pipe drain into a sewer pipe in the laundry room?

    Is there any extra-cost features worthy of considering over a no-frills hot water heater?

  2. #2
    Join Date
    Jan 2004
    Location
    Lancaster PA
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    68,594
    No, it can't go outside, and should be piped so that if the relief valve opens it will be noticed. A pan with a water sensor switch wires to a water solenoid valve can be installed. Then the relief is piped down to the pan and if it ever opens the sensor shuts off the water to the heater.
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  3. #3
    Join Date
    Aug 2010
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    West Monroe, LA
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    Quote Originally Posted by beenthere View Post
    No, it can't go outside, and should be piped so that if the relief valve opens it will be noticed. A pan with a water sensor switch wires to a water solenoid valve can be installed. Then the relief is piped down to the pan and if it ever opens the sensor shuts off the water to the heater.
    I agree with Beenthere. The device/shut off switch that I recommend is called a Wags valve. It will stop the water flow if senses water. I have this this device save countless homes for damage $$$.

  4. #4
    Join Date
    Mar 2009
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    Mount Holly, NC
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    3,422
    I also agree. the purpose for it, is to vent water and steam if the limit fails to turn off the heater. without it, the water tank is a bomb. with it plumbed as it is, it can fill your basement if a problem occurs while you are not home.
    while everyone would like an in ground swimming pool, I doubt you are prepared for it...
    an auto shutoff is needed.
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  5. #5
    Join Date
    Sep 2009
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    13
    Quote Originally Posted by beenthere View Post
    No, it can't go outside, and should be piped so that if the relief valve opens it will be noticed. A pan with a water sensor switch wires to a water solenoid valve can be installed. Then the relief is piped down to the pan and if it ever opens the sensor shuts off the water to the heater.
    If the water supply is shut off and all the remaining water leak out of the water heater, would the burner still turn on to attempt to heat the empty water tank?

  6. #6
    Join Date
    Sep 2005
    Location
    Atlanta GA area
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    Quote Originally Posted by leakyduct View Post
    If the water supply is shut off and all the remaining water leak out of the water heater, would the burner still turn on to attempt to heat the empty water tank?
    Theoretically if the gas valve failed (failed as in stayed open to fire the burner)... yes. However this would be rare.

    If I remember (heat and AC folks do not always do plumbing), code requires the safety T&P (temperature and pressure) valve overflow pipe to go downhill. If the DWH (domestic water heater) is in the basement already... then going uphill to outside (outside is allowed in my area) is not acceptable. Note codes change as time goes on... when something is replaced it generally needs to be done to the current (usually stricter) code.

    Have you thought about a tankless system. Endless hot water, slightly lower gas bills... yet install is high $$$'s (sorry, we cannot post prices here... contact a local contractor that does tankless).
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  7. #7
    Join Date
    Aug 2012
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    2,720
    There's no drain in the basement floor? Yea what beenthere said.
    My name is TooCoolforschool and I am a chronic over charger.

  8. #8
    Join Date
    Feb 2010
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    Metro Atlanta, GA
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    475
    Quote Originally Posted by leakyduct View Post
    If the water supply is shut off and all the remaining water leak out of the water heater, would the burner still turn on to attempt to heat the empty water tank?
    The WAGS valve mentioned shuts off the water and the gas (Water and Gas Shutoff = WAGS). I've had a few that have had to do their job and they worked well but unless they've changed the design they're a one time deal. Once they kill everything they have to be replaced. There's another, similar product that is resettable that we had some decent luck with but I can't remember it off the top of my head.

  9. #9
    Join Date
    Aug 2010
    Location
    West Monroe, LA
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    Quote Originally Posted by FlyersFan View Post
    The WAGS valve mentioned shuts off the water and the gas (Water and Gas Shutoff = WAGS). I've had a few that have had to do their job and they worked well but unless they've changed the design they're a one time deal. Once they kill everything they have to be replaced. There's another, similar product that is resettable that we had some decent luck with but I can't remember it off the top of my head.
    You are correct about the wags valve. It's a one hit wonder. If it every gets used then you will have to replace it. Great product none the less can save you some $$$ when installed propely.

    My company does both heating & cooling along with plumbing. So even though I work on the heating and cooling side, I see the plumbers use these all the time. Also both the heating and cooling along with the plumbing sale a lot of water alarms. While water alarms are good they so have their draw backs. If no one is home then it will do you no good as it just lets you know that water is present by sounding a alarm noise much like a smoke detector.

    Our company offers a water protection package which includes on the heating and cooling side a water alarm, in line safety switch, pan float switch and a flow plus treatment device that treats the condensate line with tablets to help to prevent line from stoping up.

    On the plumbing side we offer the same package for water heaters but with diffrent things. Water alarm, drain pan, wags valve and stand. The reason we suggest a stand is due to some customers water heaters in my area like mine being installed in the middle of the home in which TMP line needs to go to floor drain in a hvac heating closet that stubs out 2-3 foot above the slab. Without a stand there would be no way to have the TMP ran properly without it.

    Also you might also want to look into a Tankless water heater. I would never ever suggest electric one or the use of one with propane due to added cost with no real ROI. While even with a natural gas tankless heater the ROI is many years. But then jus like higher seer heating and cooling systems they have there place but if looking for just energy efficient increase vs payback then either or will take a while to recover. Many people have look past the ROI and see it for what it is or offers which is a better degree of comfort with higher seer system and endless hot water with a tankless.

  10. #10
    Join Date
    Nov 2004
    Location
    SW FL
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    6,387
    http://www.geappliances.com/heat-pump-hot-water-heater/

    or similar,
    MIGHT work in some situations, BUT it's certainly NOT for everybody.
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  11. #11
    Join Date
    Jun 2007
    Location
    Minneapolis, MN
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    751
    Technically what you describe is a temperature and pressure relief valve (T&P), which is intended the consumer from an water heater stuck in full fire mode. The T&P should terminate about a foot from the floor full bore and the end should not be threaded as they often leak - mostly from fatigue and folks want to cap them off to "fix" the leak. Water heaters rarely flood but rather start as small leaks getting progressively worse. Annual inspection is usually sufficient to guard against water damage and a pan with alarm is often used on upper level installations. If the T&P leaks, you want to know about it and have it replaced.

    If you shut off the water main, as I do, when on vacation, you will have no worries...like the wash machine hose bursting, which is much more common and serious.

  12. #12
    Join Date
    Aug 2004
    Location
    S.E. Pa
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    The code is very specific on TPR valves and drains. They must terminate within 6" of the floor in a conspicuous place. That means they want a human to see it happening. This discharge may be through an air gap into a funnel to a drain pipe or into a pan, which is then drained according to the plumbing code. You can install an inexpensive wet switch/ alarm to alert the presence of water. The WAGS is a lot more money and more to go wrong.

    If the room where the tank is located is of finished construction or in proximity such that a leak or discharge at the WH would cause damage to permanent finished construction then the tank must sit in a pan to drainage.

    The discharge tube must be the same diameter as the valve (3/4") and of rated material meaning no PVC. No threaded end as stated previously because to cap the tube could cause an explosion. No shutoff valves and must drain downhill.

    Valves should be tested annually by tripping the lever to confirm discharge (into a bucket) and replace the valve every 3 yrs. See mfr. for additional info.

    If you have a pressure reducing valve or backflow preventer on the water main, you will need an expansion tank on the cold inlet.

  13. #13
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    Sep 2005
    Location
    Atlanta GA area
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    Quote Originally Posted by hearthman View Post
    The code is very specific on TPR valves and drains. They must terminate within 6" of the floor in a conspicuous place. That means they want a human to see it happening. This discharge may be through an air gap into a funnel to a drain pipe or into a pan, which is then drained according to the plumbing code. You can install an inexpensive wet switch/ alarm to alert the presence of water. The WAGS is a lot more money and more to go wrong.

    If the room where the tank is located is of finished construction or in proximity such that a leak or discharge at the WH would cause damage to permanent finished construction then the tank must sit in a pan to drainage.

    The discharge tube must be the same diameter as the valve (3/4") and of rated material meaning no PVC. No threaded end as stated previously because to cap the tube could cause an explosion. No shutoff valves and must drain downhill.

    Valves should be tested annually by tripping the lever to confirm discharge (into a bucket) and replace the valve every 3 yrs. See mfr. for additional info.

    If you have a pressure reducing valve or backflow preventer on the water main, you will need an expansion tank on the cold inlet.
    Was gonna mention this... In my area ALL DWH installs must have an expansion tank. Most of the T&P failures I have seen over the years are due to not having an expansion tank installed.

    I really like tankless... however one needs to realize they are not about energy saving (one will not get a payback to save $$$). Rather, they are about comfort in the sense of endless DHW... however one tends to use more HW when they have it. And tankless units need annual maintenance... they need to be flushed. Cost is generally a service call with some extra $$$ for supplies and procedure... cost depends on pricing in your area.
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