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EK1 Near Limit Aquastat

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NEMatt
NEMatt Member Posts: 87
in THE MAIN WALL

Had my 12 yo Energy Kinetics storage tank lower seam give up the ghost yesterday and plumbed in a typical AO Smith 100 as a replacement.

All connections are essentially as they were with the prior EK tank with minor differences for nipple placement and tank height etc.

I wired the tank to bypass the heating elements and run heating calls off that lower thermostat.

It seems to me like the boiler is running nearer the high limit during a domestic heating cycle now before the heating call extinguishes.

I assume there might be two causes... 1. Dip tube. 2. Lower tstat placement.

Any thoughts from @Roger or other EK gurus?

Comments

  • HVACNUT
    HVACNUT Member Posts: 7,584

    Use the upper thermostat.

  • NEMatt
    NEMatt Member Posts: 87
    edited June 27
    https://forum.heatinghelp.com/discussion/comment/1899246#Comment_1899246

    Wouldn't that make it even worse?

    In my mind the long dip tube is just pumping water that just left the PHE right down near the tank drain where it gets sucked back up into the PHE. That just gets hotter and hotter without ever really stratifying in the tank. Seems like it would take even longer for the upper stat to reach the setpoint than the lower one which is closer to where the tube is dumping hot water.

  • 109A_5
    109A_5 Member Posts: 4,290

    If the boiler is running at a high temperature during a DHW call / recovery I would think the overall heat transfer efficiently is not as good as the former tank. Maybe the dip tube need to be shorter like in the picture. Was the dip tube length of the new tank matched to the old tank ?

    image.png
    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • HVACNUT
    HVACNUT Member Posts: 7,584
    https://forum.heatinghelp.com/discussion/comment/1899256#Comment_1899256

    Yes, disregard. I was looking at the EK piping and pictured in my head your tank without a dip tube.

    If its approaching high limit, there's poor heat transfer. Can you check in and out temperatures on both sides of the plate HX? Do you have the manual to see how to back flush the HX?

  • hot_rod
    hot_rod Member Posts: 28,010

    The new tank may have heat a trapper nipples on the cold side, reducing the flowrate.

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    GGross
  • NEMatt
    NEMatt Member Posts: 87
    https://forum.heatinghelp.com/discussion/comment/1899265#Comment_1899265

    It does have blue plastic pieces in both upper nipples that decrease the ID a fair bit. I'm not sure if they are molded straight in as part of the dip tube though. The tiny black heat trap flapper surely isn't reducing flow rate, I can basically blow on it and it opens.

  • NEMatt
    NEMatt Member Posts: 87

    @109A_5 No, I didn't think about it till I was watching the boiler run. EK has a little instruction on modifying dip tubes to mimic theirs. I believe this is the main source of the issue

  • Roger
    Roger Member Posts: 484

    Thank you all for your posts.

    @NEMatt , I suspect that once you modify the dip tube as Energy Kinetics instructs, you will be restored to proper operation. Right now I believe the hot water is going to the bottom of the tank, and the cold water is pulling from the bottom of the tank, so it’s essentially bypassing, which makes it look like poor heat transfer.
    I don’t have the diagram on my phone, but if needed, please contact our tech support team on Monday if you need further instructions on converting the electric tank.

    It is possible that there is some other restriction, but piping the tank properly is the first step.

    Best,

    Roger

    President
    Energy Kinetics, Inc.
    Robertw
  • NEMatt
    NEMatt Member Posts: 87
    https://forum.heatinghelp.com/discussion/comment/1899318#Comment_1899318

    Thanks for chiming in.

    I'll be modding the dip tube tomorrow and that'll hopefully get it squared away.

    I plumbed it almost exactly like the original tank, the only exception being one additional 90 on the 3/4" pipe and the smaller ID moulded plastic in the tank nipples. I back flushed the PHE for good measure so I doubt it's a restriction.

  • Robertw
    Robertw Member Posts: 92

    @NEMatt

    You can message me if you need any help with the dip tube dimensions. No sense in bothering my boss for it, or any other questions for that matter.

    Robert W.

    Energy Kinetics

  • Roger
    Roger Member Posts: 484

    You’re welcome, @NEMatt - it sounded like you were on to the right solution before I commented.

    From Rob’s post, just to clarify, It’s no problem, I enjoy contributing, but I’m out of the office today and appreciate his help!

    Roger

    President
    Energy Kinetics, Inc.

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