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Replacing Hot Water Storage Tank with Hot Water Heater - System 2000

beyondvoid
beyondvoid Member Posts: 10
I have an EK1 System 2000 (oil) which includes a 40 gallon storage tank, the water is heated through a heat exchanger. The tank leaked out yesterday and I am looking to replace it. I am considering purchasing a standard 50 gallon electric or gas hot water heater and using it as a replacement storage tank (i.e, unpowered and not hooked up to electric or gas).

The current storage tank (model # 0823145) has two thermostat wires that come through the top and connect to the boiler for temperature control.

My question is, is there any reason I shouldn't be able to just tap off of the thermostat input in a new hot water heater and run this to the boiler? A search on the internet implies that people have used hot water heaters as storage tanks, but I want to make sure this sounds doable before doing the work!

And yes, I will also be looking into a direct replacement for the tank, but I suspect it will be triple the price so I want to weigh my options.

Any help is greatly appreciated!

Comments

  • psb75
    psb75 Member Posts: 474
    To be clear: what was the original purpose of the tank that went bad? And then what purpose would you like the new tank to perform? You are calling the old tank a "storage" tank. Do you mean that it was a buffer tank--storing heat for the house? Or was it a domestic hot water indirect tank? If you are looking for a "buffer" tank you could do what you are planning.
  • beyondvoid
    beyondvoid Member Posts: 10
    Thanks for the reply. I'm not exactly sure how to answer that, but I think a buffer tank is correct. The boiler heats the water in the tank indirectly through a heat exchanger. Water comes into and out of the the tank via a tee at the drain pipe & inlet at the top, circulated heated through an external heat exchanger and returned to the tank. Here's the overview of the system:

    https://energykinetics.com/system2000-quietest-most-efficient-boiler/

    My biggest concern is that the thermostat wires are accessible on a hot water heater unit (I've never had a traditional hot water heater) but from what I've looked at online, it should be.
  • SuperTech
    SuperTech Member Posts: 1,689
    @psb75, the original poster was using the correct terminology.  The Energy Kinetics system 2000 uses a brazed plate heat exchanger and a bronze circulator to make and store domestic hot water.  The tanks EK uses are just repurposed electric hot water heater tanks without the elements.  Chances are that the tank failed due to lack of maintenance such as anode rod replacement, or perhaps just age and wear. 

    @beyondvoid, I'm pretty sure that EK offers a replacement tank that comes with a ten year warranty.  Thats much better than what you would get from buying an electric water heater,  modifying it and then using it for something other than the manufacturers intended purpose. I think the manufacturers tend to void warranties when products are not used as intended.  
    STEVEusaPA
  • Roger
    Roger Member Posts: 207
    edited February 13
    Thank you for your question @beyondvoid and for everyone’s posts. 
    Energy Kinetics’ tanks are specially engineered and optimized to take advantage of thermal purge with the plate heat exchanger. That arrangement can save up to 10% off an annual fuel bill vs a conventional indirect water tank with coil as the boiler can thermal purge and recover the heat left in the boiler; coil type tanks can’t because coil is hot in the middle of the tank. 
    Energy Kinetics’ tanks include a special dip tube plus a thermostat that is higher up in the tank than the lower thermostat location on typical electric tanks. We do offer electric tank conversion kits with instructions.
    For reference, we will not void your boiler warranty if you are not using and Energy Kinetics tank. Also, tank manufactures have indicated that tanks will last a much longer time or even indefinitely if the anode rods are replaced and there are no site specific problems. 
    Best,
    Roger 
    President
    Energy Kinetics, Inc.
  • archibald tuttle
    archibald tuttle Member Posts: 819
    @Roger it looks like you are saying that OP's tank had a sacrificial anode that could have been replaced (i'm assming it was your tank although i'm not schooled on your model #s).

    And on the system theory, there is a circulator for the domestic tank that pulls cold water from the bottom if the thank and returns heated water to the top of the tank to help purge heat from the boiler after cycle?

    One question I have is, if using hot water doesn't the tank thermostat force the boiler to run until the temp is satisfied, or maybe if the thermostat is located in the top of the tank there remains some cool water in the bottom to accept purge heat even thought the thermostat is satisfied?
  • Roger
    Roger Member Posts: 207
    edited February 14
    Thank you, @archibald tuttle.  

    The tanks do have a sacrificial anode rod, although like all tanks with replaceable anode rods they are tightly installed and not easy to remove and replace.
    The circulator arrangement heats the tank “from the top down”.  The location of the aquastat in the tank creates a reservoir of cold water at the bottom, which is nearly perfectly balanced with the amount of heat left in the boiler.  This results in a very effective thermal purge, without any complex controls.  The entire tank finishes hot and the boiler finishes cold. This virtually eliminates both off cycle losses and oversizing losses.
    Drawing the cold water off the bottom of the tank and heating it through the heat exchanger and pumping it into the special dip tube at the top of the tank allows for a very fast recovery.  The heated water is right where it’s drawn from to feed the fixtures for very good and responsive hot water temperature quality as well.
    Tanks with coils become less productive as the tank heats because the temperature difference continually decreases. The heat exchanger arrangement allows the full output of the boiler to heat the tank through nearly the entire cycle.
    Roger
     
    President
    Energy Kinetics, Inc.
    Larry Weingarten
  • archibald tuttle
    archibald tuttle Member Posts: 819
    edited February 14
    @Roger thanks for your reply. you can be my heating valentine for being the CEO that responds on sunday. my wife is already no doubt upset that i spend this sunday thinking about abstract problems in the warming of civilization. back to the homefront momentarily but more questions.

    I would think that the cold reservoir and purge has got to relate a little to duty cycle and cycle length which i'm sure are contemplated in the control algorithms although i would imagine that at cold times with limited DHW use maybe the purge recovery is not as complete, which is no criticism of the approach. I like the approach. I built a purge recovery to my warm floor flywheel heat exchanger tank (my warm floors are all polybutyl so i separate the hydronic circuits.)

    but i do hope to remedy my lack of awareness of your boiler product. i admit, i'm intrigued. it looks like you obtain low stack temperatures by the long spiral dwell of the combustion stream. I can't really tell from the pictures if the spiral is constructed from water tube heat exchangers although it sounds like it would be a medium without the thin gaps of something like the munchkin style water tube where the exhaust goes through the small gap between water tubes.

    it seems the combustion chamber is removable. what about the combustion spiral. the thing that bugs me about the munchkin is you have to dismember the gas and unpipe it in order to get the spiral out of the boiler so most often it is cleaned in place with the 'credit card' method which is effective but drops any scale into the 'sump' where it is almost impossible to clean out well with the drain located in the middle bottom of the unit. i have installed them up on blocks with some access to remove the condensate drain so they can be rinse out or the small drain hole cleared, but I would much prefer a design where the heat exchanger has unions and can be easily removed. Especially where this looks to be a tri-fuel approach, I would be hoping for detachable cleaning so I could take the combustion spiral outside and spray it off with a pressure washer (and easily replace if it fail, which again is intended as a reflection on your product comparatively but just an understanding of the generally lower mass heat exchangers in modern boilers.

    I wish I had just been able to go the AHR show and see one for myself if there were such a thing as the AHR show. Do you have a dealer network that has stationary or mobil version I can take a look at in southern new england.

    thanks,

    brian (archibald tuttle to his 'friends', see the robert deniro character in Brazil)
  • Roger
    Roger Member Posts: 207
    Thank you, @archibald tuttle - I enjoy answering questions and helping out where I can. 

    Our spiral boilers have wide open flue passes and wide-open water passes and they are very easy to clean, there are no micro flue passes or micro water passes found on most condensing boilers.  Our EK1 size cross section looks like a rectangular pipe; it’s the equivalent of a 2 1/2 inch pipe on some models and a 4 inch pipe on other models. So there’s very little restriction on hydronic side.
    The flue side is also wide open, with the smallest cross-section around 1” x 11” - you could literally throw marbles in it and pick them out as they roll to the bottom. Ceramic chambers are not to be removed for cleaning (there’s no need), however the stainless steel chamber can be removed on the models that have them. 
    Today’s oilheat and bio fuels have ultra low sulfur, so they burn as cleanly as gas and ash buildup and cleaning have been virtually eliminated.
    We follow a similar strategy on our condensing boiler, the Accel CS - we eliminated issues we found on nearly all other contending boilers. That is a fire tube design, with three-quarter inch fire tubes and “super turbulators” for easy access and cleaning if ever necessary. The waterside has wide-open passes as well, with the smallest restriction being the equivalent of a 1 inch pipe cross section.
    We have videos on our website where you can see some of these details, although we also have a fleet of live fire demo vans and trailers so you can see the equipment in the field in New England and mid Atlantic states. Contact us or PM me and we can get you in touch with our local territory manager. 

    Best,
    Roger 
    President
    Energy Kinetics, Inc.