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Cleaning a Viessmann Cast Iron Boiler

New customer called me that he just moved into a new house that has this Viessmann Vitogas ECD boiler that has completely sooted up (in-slab copper radiant, no boiler protection), spewing CO in excess of 2,000 ppm. The boiler has been shut down. As you can see, it's in a very tight alcove with little or no access to the sides; only the front and top. Has anyone ever taken one of these apart to clean the HX? Is it possible with this restricted access?

The only other option is to replace it with something like a Lochinvar floor mounted KHB boiler, but the KHB is 2" wider which would make it very difficult to pipe.

Thank you for any input!

8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

Two btu per sq ft for degree difference for a slab


  • Larry Weingarten
    Larry Weingarten Member Posts: 3,137
    Hi, Can that wall to the left of the heater be removed and reinstalled after working on things? Could it be modified to be easily removed? That’s tight!

    Yours, Larry
  • rick in Alaska
    rick in Alaska Member Posts: 1,441
    If it were me, and I am a very curious person, I would take the top panel off and would bet you would find out it cleans from the top.
    But, can a Viessmann soot up??????
  • hot_rod
    hot_rod Member Posts: 20,740
    that was a great little cast boiler, it had boiler protection in the form of an aquastat that would stop flow if it dropped below 140. Three sensors in one well for operating, high limit and return protection.
    As long as it was connected with barrier tube, I’d try and save it. Removing it if it is that badly sooted, for cleaning, might still be less $$ than a replacement

    How close to the heat load is it sized? Short cycling may have been part of the sooting issue?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    EBEBRATT-Ed Member Posts: 14,505
    @Alan (California Radiant) Forbes

    Cleans from the top. Manual attached, not sure if it is the correct one there are others on the web site. If you go to the Viessmann web site you have to find literature for discontinued products. Takes a little searching
    Alan (California Radiant) Forbes
  • @Larry Weingarten Great idea!

    @rick in Alaska When he fist called me about the flame rollout switch tripping, I thought it was just an anomaly and I told him that his boiler would last forever. Viessmann's just don't do this, but
    my experience is that once a boiler starts sooting up, it's predisposed to do it again after cleaning.

    @hot_rod I forgot about that feature about pausing the pump. It's an 80K boiler heating a 1,200 [] Eichler-style house, so yes, probably oversized.
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab
  • tim smith
    tim smith Member Posts: 2,699
    pull burner rack, remove top, tube brushes, vacuum running constantly to catch floating soot. Seal your self in so if any addl gets away from vacuum it does not float out into finished area. Was the tube in tube burners out to clear dust and dirt that will block inner tube causing poor combustion. If real bad, we have even taken boiler out and went outside and washed out.
    Good luck Alan
  • tim smith
    tim smith Member Posts: 2,699
    edited March 2022
    If you get thoroughly clean they wont be pre disposed unless burners have cracks in them. Btw, we put quite a few of the ECD and ECDS in back in the 90s and early 2000s. Good little boiler but do need burners cleaned at least every couple years to prevent sooting.