Illinois Replacing a leaky preheat tank again?

Discussion in 'Maintenance and Troubleshooting' started by JDF, Jan 21, 2015.

  1. JDF

    JDF New Member

    Can anyone help with our preheat tank problem? We live in central Illinois. We have an Envision Water Furnace with closed ground vertical loops. We use the DSH plumbed into an electric A O Smith 50 gal water tank (no electrical use but was comparatively inexpensive) for the preheat tank. Then the hot water outlet goes to a Rinnai tankless water heater that goes to a Mini Bosch 7 gal (for circulating hot water) then there is an expansion tank and a dedicated hot water line and returns back to a Grundfos Aquastat/Timer circulating pump. The problem is that the A O Smith preheat tank has failed for the 2nd time, leaking from bottom. The whole system was set up in 2007. The first failed in 2011 and now again. We have city water and it is hard so we use a water softener which is first in line from the main water line and then water goes to the A O Smith preheat tank. Not wanting to just put in another A O Smith because the plumbing cost is not worth it if the tank leaks every 3-4 years and what a mess. Wondering if there is something else wrong with the set up before we put in a higher cost preheat tank like a Marathon 50 gal with no elements???
  2. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    What is in the "city" water? Call the Water department they will know. If they say they do not know, look out. EPA makes them know and report.

    It is possible bad luck with tanks. A glass lined, (read enamel coated slip then fired can be compromised buy a fork lift any where from the factory to your home.

    Hello and welcome,

  3. JDF

    JDF New Member

    Thanks for the info. To clarify, we live within the city limits (not a well) so the water is from Illinois American. I am waiting for them to return my call. I did talk to them back in 2007 about the water content so I could adjust the water softener cycle. The water is not very good. I have been told that since we live so far out that the water sediment ends up in our pipes. Perhaps we need a sediment filter/trap right off the main line? The salt from the water softener can't be good on the plumbing? I'm thinking of replacing the leaky preheat tank with a Marathon since it has best rating for "non-corrosive" and no electrical tank might work best since the tank would not have any heating elements/anodes to rust. Not sure.

    I have read some posts here about the preheat tanks, sizing and plumbing. My DSH outlet is piped to the top of the preheat/buffer tank, whereas the diagrams and discussions here indicate that it should go to bottom of the tank. Does that really matter? The cold water inlet to the tank would have a dip tube putting the cold water to the bottom of the tank. Then the hot water from the DSH attached to the top tank would keep the hot water at the top of the tank. (Doesn't mix with the cold water at the bottom?) I attached a picture that shows the plumbing. The shut off valves are looking rusty. Mixing metals? Also, there is grounding wire on the main cold line into the house which looks like it runs to the electrical panel. Does the preheat/buffer tank need to be grounded?

    Attached Files:

  4. heatoldhome

    heatoldhome Geo Student Forum Leader

    I'm probably not the best one to try and discribe this but here goes.

    The salt in the water softener dose not end up in the plumbing. Inside the softener you have a "element" that collects minerals and stuff in the water. When this element starts to get full it needs to be flushed. The softener will switch a valve taking it self off line (out of service) then will flush itself with salt water due to the minerals and stuff attaching to the salt and flushing down the drain. Then it flushes again with fresh water and switches back to in line service.

    No salt should go into the water supply.

    This is probably better explained in full by somebody else. But hopefully you get the idea.
    Last edited: Jan 23, 2015
  5. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    Were the anodes removed from these tanks?
  6. JDF

    JDF New Member

    There is one anode. It was not removed from the tank.
  7. JDF

    JDF New Member

    That makes sense on the softener and salt. Thanks. When I called A O Smith last week about the leaky tank and whether the warranty applies, they told me that the salt from water softener was bad on the tank??? and that they have a 1% failure rate and that my tank failure was due to the water quality and the salt. Hmmmm?
  8. heatoldhome

    heatoldhome Geo Student Forum Leader

    Generally speaking soft water is better for water heaters.

    When you rapidly raise the temp of water minerals tend to "fall" out of the water (no longer suspended in the water).
    These minerals will build up in the bottom of the water tank.

    Mineral buildup in the bottom of the tank is not good.

    This is also why insta-hot type (tank less water heaters) will plug up once in a while and need a acid flush.

    Again I missed some technical terms and such. But hopefully you get the idea.

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