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Any good ideas how to clean this heat exchanger?

Harvey Ramer
Harvey Ramer Member Posts: 2,239
This is what happens to a cast iron cold start boiler with no boiler protection.


  • Harvey Ramer
    Harvey Ramer Member Posts: 2,239
    More pics

    Notice the circulator. There was a knuckle head here. Also the oil pressure was turned down to 50 psi. I guess that's what knuckle heads do when the heat exchanger starts to clog.
  • Weezbo
    Weezbo Member Posts: 6,232
    Call the chimney Sweep,First.

    I have seen Viessmann suffering from the same abuse .

    Can you Make it go ?

    No ,

    Then how come it was running just now?

    because i wanted to determine something ...

    How do you Know it is the chimney?

    because it is pulling what air it needs around and around through the barometric damper thru the burner . this 5 X 6 room with no make up air does not allow it to breath..

    well, couldn't we leave the door open ?


    outside ... a few mins later ..

    The stack looks clean to Me

    oh it does well how about this ?

    i hassle around getting the condensated stainless cap off the vent and have him dig at it a bit

    "The stack looks clean to Me."rings in my ears as he cannot get my two pound screwdriver 14 " long to penetrate the crappola...

    for now let me give it a go .. and i bust like a two foot piece out rock of the stack....

    lets go back inside for a moment where i take the stack loose and shovel like 5 bags of stuff out of the thing so that i can see daylight ..and clean the pipe a bit and make some means for something to get out of the boiler at the breech lol..

    And not letting him see i fire it again ..

    with the door open and then shut it down ...

    you called me over here to tune it for you because it was not running well, it runs ..

    buh until or unless you have the stack cleaned i can do neither .

    call me when it is done.

    here's my bill you are entitled to a second opinion ..

    it is your home buh to turn this on puts your neighbours lives at risk .

    so that is why the safety shut this down .


    similar story?

  • TonyS
    TonyS Member Posts: 849
    Water clean it

    Pipe the vent off the back so you can open the top of the boiler and start it. Use a small sprayer and shoot water down the sections after the boiler is near temp. Dont flood it.

    All that crap will steam off and go right up the chimney.
  • Harvey Ramer
    Harvey Ramer Member Posts: 2,239

    The very first picture is the top of the heat exchanger with the top of the boiler open. Some of it was loose which I could remove. I found though that the crap is caked in between the exchanger sections so damn tight it is like concrete. There was one small section I could get my brush down through. I guess that is where it got it's last breath. It may be past the point where the water trick works.

    I would sure hate having to pull all the boiler sections apart. Maybe it's time for a new boiler? The piping needs redone anyway.


    This home owner is not the kind you mentioned. He recently bought the house so it is not his fault. Also he is a mechanical engineer. From my experience they are a little more understanding when it comes to this kind of stuff.

    The evidence would suggest that the trouble started with the knuckle head who converted the system from gravity. Condensing flue gases on the heat exchanger. That wetness kept accumulating soot. Looks like the heat exchanger was never cleaned. He probably did not know you have to open the top of the boiler. As it clogged and started to gasp for air, it looks like he started to turn down the oil pressure to keep it from smoking so much. Bad idea. Clean the heat exchanger, stupid! So it kept going till last night it finally smothered itself and I had to go out after hours, to no avail. The chimney, by the way, is open.
  • kcopp
    kcopp Member Posts: 4,393

    if you need to spend a day or more cleaning it they may just as well go for a new boiler.
  • Steamfitter66
    Steamfitter66 Member Posts: 117
    A brush and water

    i have used a section brush and a hose with a nozzle. you will then need a new door seal, target and floor. Its by far the fastest way if you have a floor drain near by. Bunny suit for the guy doing it. Mask as its carcinogenic.
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