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Buderus ST 150indirect H/W Replacement?

Great site!!

I have Buderus ST150 Water Heater 52.8 GAL (Indirect Blue Thermoglaze) working with a GB142 wall mounted propane boiler. Both pieces are 9 years old.

My boiler is blowing off through the TPR valve at 32 pounds. I have it isolated to the indirect unit and feel that the coil is leaking.

I have lost faith in Buderus and plan to replace the boiler in the future and the indirect ST150 very soon.

Question: If I change out the ST150 what would people replace it with? I have a sensor from the boiler to the indirect that will need to stay connected.

Any insight would be great.




  • heathead
    heathead Member Posts: 234
    I like the Viessmann Indirect water heater models that are stainless steel. The Buderus sensor should fit into the well on most any indirect water heater. That being said make sure you test your water because high chlorides and stainless steel don't work well together. If you have high chlorides i like a stone-lined tank. Good luck
  • GBart
    GBart Member Posts: 746
    STONE LINED?????????????????

    no too heavy, if you have high chlorides-- city water with lots of chlorine in it-- go with a standard glass lined steel tank
  • GBart
    GBart Member Posts: 746
    I'm thinking the old stone lined, I think you mean the new light weight like this

    https://file.ac/ZnjQT1P3uw8/Alliance LT & SL Product Data Sheet.pdf
  • Canucker
    Canucker Member Posts: 722
    > @GBart said:
    > STONE LINED?????????????????
    > no too heavy, if you have high chlorides-- city water with lots of chlorine in it-- go with a standard glass lined steel tank

    Chlorides are salts, not chlorine. Both will kill your tank in short order if they're too high
    You can have it good, fast or cheap. Pick two
  • clammy
    clammy Member Posts: 3,094
    I had a few buderus st150 tanks fail ended up replacing w bock indirect aside from no clean out port there recovery and performance was just as good as the buderus in my eye .the bock has a pretty decent heat exchanger and the price point was better then buderus . I also would mention that u must chk or replace anodes yearly and in the larger tanks I believe there’s a anode off the hot water outlet . In the future I’ll add a scale filter as other have suggested . I also would suggest flushing the tank every month or so . One other note I would suggest when u replace ur tank after filling and before turning ur boiler back on chk ur boiler controller for ur tank temp before start up and time how long it takes and write it down on the tank this way over time u an chk and compare for performance difference would also look at delta t across tank .check also if the boiler has reached it temp setpoint and look at portable and boiler temps . If you find the boiler cycling on hi temp before tank is satisfied chk ur pump flow delta t and go back to want u had logged from the original install makes it quite easy to diagnose when ur coil has build up . As always a lack of flushing and monitoring of recovery times and possible lack of water treatment all lead to poor performance and premature failure .peace and good luck clammy
    R.A. Calmbacher L.L.C. HVAC
    NJ Master HVAC Lic.
    Mahwah, NJ
    Specializing in steam and hydronic heating
  • TAG
    TAG Member Posts: 755
    It's a shame that the new Buderus Thermoglaze tanks don't last -- The model previous to those did. One of mine is 25 years old and the other I just replaced last year.

    I used the all SS Buderus for replacement -- mostly because I was worried about how the temp sensor from the eccomatic woudl work. The Buderus had the well. Hope the SS holds up ....

    I'm using the Viessmann in the new place w/ V boiler

  • Henry
    Henry Member Posts: 996
    We replaced the Buderus tank with a HTP S/S indirect.