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Update on Buderus GB142-30 exhaust issues

fosterdl Member Posts: 21
I posted a couple weeks ago on the corrosion the tech found in my Buderus GB142-30. Since then the unit shut down and I needed a call back. This time I got my regular tech and once again he found that the outside of the boiler heat exchanger was plugged with a deposit that looks like light grey lava rock. (photo 4 four) The boiler was installed in 2005 and the first time he found the deposit was about 2007 and it's been an annual cycle ever since. So in my last post some of you guys gave me some excellent advice and I've made changes since then. I eliminated the 10' exterior exhaust riser (photo 1 one)and now the exhaust terminates just outside the cellar wall for a total of about 5' of pipe. I also eliminated the high riser on the condensate trap. (photo 2 two) However during the installation of the new trap (photo 3 three) the male adaptor into the drain tee must have loosened up and now I have another question. As you can see, after about one week of use, the trap has grey streaks on it where the condensation has run down the sides of it. My question is" why is my exhaust condensate grey in color? This is the same grey that accumulates around my heat exchanger and plugged up my last trap.


  • Xmytruck
    Xmytruck Member Posts: 85
    I would guess that you HX has a crack. My traps and condensing pump water is black and I have a crack HX. But I am not a pro
  • Zman
    Zman Member Posts: 6,989
    Have you done a combustion analysis?
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Bart Vaio
    Bart Vaio Member Posts: 56
    We service quite a few GB's and this is not an uncommon deposit. How long between the last full service? Looks like poor combustion byproducts. What are the designed fluid temps?