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Knight boiler problems

Leisole
Leisole Member Posts: 1
in THE MAIN WALL
We had a new boiler put in about four years ago. It is a Knight WB 105 attached to a very old hot water system. We have it serviced every season, but this year we received the "Fan Speed High" lockout. Our serviceman discussed the problem with the Lochinvar Rep. and recommended a controller board replacement. We did that to no avail, so the next step was the fan, so after we disassembled the front to replace the fan, we decided to clean the combustion chamber. It was piled with rust pellets. Not just a little. It was a huge pile.



Is this normal, or are we looking at a bigger problem?
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Comments

  • bld999
    bld999 Member Posts: 47
    Prev. servicings

    How much debris was in it the first two servicings?
  • Leisole2
    Leisole2 Member Posts: 23
    Knight boiler

    Sorry, I lost my account somehow. To answer your question, not

    Much . Maybe a dusting of rust pellets, but not flowing over the ridges like it is.
  • Zman
    Zman Member Posts: 7,611
    Combustion analysis?

    Was a combustion analysis done initially or at the servicing?

    Do you have the results?

    Carl 
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Eastman
    Eastman Member Posts: 927
    where

    could that physically come from?  Is it actually rust?  Or some kind of combustion byproduct?
  • Zman
    Zman Member Posts: 7,611
    Good question..

    Where is the air intake/exhaust  located. Do you have a picture?

    Carl
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Leisole2
    Leisole2 Member Posts: 23
    Combustion check

    There was a combustion analysis when the system was installed, and one a few weeks later, but not one since. Most of the other aluminum parts are not pitted, so I didn't think we were getting the corrosive effects from a bad burn cycle. We won't be able to get one done until we are out of lockout. My worry is that all of this rust may be effecting the airflow, subsequently causing the fan speed problem.
  • Leisole2
    Leisole2 Member Posts: 23
    Intake/out lines

    The exhaust was detached to do a airflow test. It is a side exhaust with about a 6.5 ft rise
  • Zman
    Zman Member Posts: 7,611
    I am wondering....

    On the outside of the building, what are they near?

    If they are too close to each other they can cross contaminate.

    Are the in a spot where they can suck in contaminants? Could kids throw dirt in them?

    That is a LOT of debris.

    Carl
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Leisole2
    Leisole2 Member Posts: 23
    Worries

    I thought the consistency in size and color of the debris looked like a single contaminant but here is a shot of the outdoor intake/ exhaust vents. They are closer than I remembered.
  • Eastman
    Eastman Member Posts: 927
    that is bad

    but do you still have some of the material you found in the boiler?
  • Leisole2
    Leisole2 Member Posts: 23
    Still have the junk

    I did not vacuum it out so I could show it to another pro.
  • Eastman
    Eastman Member Posts: 927
    edited October 2013
    handle with care

    It's my understanding that carcinogens are present inside the combustion chamber.



    I was going to suggest some chemistry experiments, but given the potential harm, I think it's best to leave it to the insured.
  • bld999
    bld999 Member Posts: 47
    carcin

    The material looks to be the same stuff that shows up in boilers using that hx, just more than usual.



    What info. do you have about it being "carcinogenic"?
  • Nom_Deplume
    Nom_Deplume Member Posts: 91
    open secret

    The coffee grounds that collect on these heat exchangers are a big problem that manufacturers won't admit to. Many years ago there was a "mouse turds" thread here that was ultimately deleted. No one knows where these granules come from, but the HX is getting stained and pitted at the same time, and ultimately it will develop pinholes.



    People say you need a combustion analysis, but this is inorganic material, it is not carbon and so it is not coming from the gas. It may be leaching out of the stainless steel. I may be wrong, but the fact is, everyone makes up stories; there is no openly available analysis of what the coffee grounds are or an understanding of why they form.
  • Leisole2
    Leisole2 Member Posts: 23
    edited October 2013
    Really?

    That's the first I've heard of that. I'm not sure of the grade of Stainless they use, but that becomes a big worry.



    Usually stainless pitting happens after aluminum pitting, due to the fact both create an oxide layer for protection. Aluminum Oxide has a higher dissociation strength, but tends to be less pervasive than Chromium (the Stainless in stainless steel) as most forged materials tend to have more impurities than highly processed alloys like stainless. Though the debris does have the brown look of iron oxide.
  • Eastman
    Eastman Member Posts: 927
    target wall

    If I remember correctly, the target wall material can be hazardous if inhaled.  I think it spalls off some kind of fiber if disturbed that easily gets airborne and inhaled.  Not to say that rust is from the target wall, but just that it may be contaminated.
  • Stekay
    Stekay Member Posts: 36
    Further discussion

    Here's the thread from the "Gas Heating" forum.

    http://www.heatinghelp.com/forum-thread/127942/Strange-residue-in-Giannoni-heat-exchanger
  • Paul Pollets
    Paul Pollets Member Posts: 3,663
    Problems

    That the vent termination is cross-contaminating the combustion fresh air intake is certainly a big problem in this installation. A 12" x 24" separation is required by most manufacturers.

    I'd be using PPE for the boiler flue, rather than PVC or CPVC.



    We have over 100 Viessmann Vitodens installed in the field; most have mouse turd accumulation after 2 years. (316Ti stainless) We try and convince the owner to clean and service yearly. Most listen.

    Seen one HX failure in a Vitodens 200 after 7+ years of no cleaning and service. There were at least 2 or 3# of debris sitting on the HX. Pinholes within the HX surfaces. Totally clogged!!
  • Nom_Deplume
    Nom_Deplume Member Posts: 91
    original "mouse turds" thread

    The original report (and subsequent long thread) was deleted, but I don't know why:



    http://dev.heatinghelp.com/forum-thread/86527/mouse-turds-on-Munchkin-HX
  • Bob Bona_4
    Bob Bona_4 Member Posts: 2,083
    the termination

    Doesn't look right. Check the IO manual. It must be to the letter. Is there some structure above too? Picture is dark.
  • Leisole2
    Leisole2 Member Posts: 23
    Thanks!

    Sorry I did not get back last night on this. I've talked to another pro who is taking a look at it. The "mouse turds" seem to be very common. Thanks for the link.
  • Leisole2
    Leisole2 Member Posts: 23
    Separation of the Intake/Exhaust.

    We are replumbing the Intake vent for better separation. The exhaust is our critical factor there due to the space outside and rise/run space issues in the house.
  • Leisole2
    Leisole2 Member Posts: 23
    Which termination are you referring to?

    I'm not sure which termination you are referring to in your comment. We had most of the upper electrical unplugged since we replaced the controller board. The fan should be in soon.



    That's the other weird thing. After we pulled the fan, i checked it thoroughly, and can't for the life of me figure out why the fan is defective. The speed seems correct, and there are no apparent flaws on the board, let alone the fan speed readings are the same as when the boiler was operating nominally.



    Back to your question, I can get better pictures if you like. Just tell me what you would want to see.
  • Leisole2
    Leisole2 Member Posts: 23
    Thread

    Thanks for the link. I was looking around for something like that.
  • Canucker
    Canucker Member Posts: 722
    He would like

    additional pictures of the exhaust/intake lines that terminate through the glass block wall. Those need to be done according to the manufacturers approved installation instructions.
    You can have it good, fast or cheap. Pick two
  • Eric_32
    Eric_32 Member Posts: 267
    Has anyone

    confirmed there are no obstructions in either the intake or exhaust piping? I really don't like the wide open exhaust with no screen on the outlet.



    We have always used the factory termination kit that comes with the boiler. Last year had a bad vibration from the fan motor, spinning out of balance getting an error code.



    Disassembled it to find a mouse in there all smashed up. He ate thru the plastic grate of the factory termination and found his way to the combustion fan.
  • ced48
    ced48 Member Posts: 469
    Concentric Vents?

    Is the run of the mill concentric vent installation in danger of cross contamination? If so, why do boiler makers allow, or promote their use?
  • Leisole2
    Leisole2 Member Posts: 23
    Sorry I did not get back

    We had a huge storm com through last night. Had to prep everything.



    The covers had been taken off to check for obstructions. These are typical 1/4" grate covers. At this time, we are repiping the intake for better separation.



    There are no blockages within the piping system or the Boiler. We have run tests (with the ten seconds we have before Lockout) to confirm no blockages within the boiler itself as well. The condensate pipe is clear. The only major thing we found was the inordinate amount of debris in the HX.



    At this point, we are waiting on the fan to come in and crossing our fingers that works.



    I will get better pictures today.



    Thanks for all of your help, this has been great!
  • Leisole2
    Leisole2 Member Posts: 23
    edited November 2013
    Oops, double post

    Nothing to see here...
  • Eastman
    Eastman Member Posts: 927
    normal vent

    I don't think it's concentric, it's just close together.



    The shear quantity of debris puzzles me, if we are to believe the leading theory, than a rather good chunk of the heat exchanger has been converted to rust.  This just doesn't seem possible though after seeing photos of this nature.  Until someone demonstrates conclusive evidence to the contrary, I would assume it's from the gas, air, or a combination of the two.
  • Gordy
    Gordy Member Posts: 9,546
    edited November 2013
    Magnet

    Did you test the material to see if it is magnetic?



    Did you personally witness the yearly cleanings



    I think you had fouled intake air. Or some pretty fouled gas mixture.
  • Steve Whitbeck
    Steve Whitbeck Member Posts: 669
    vent

    You need to raise the exhaust pipe at least 18 inches and put a 45* angle at the top and put a stainless screen in it.

    The heat exchanger is very dirty, Clean out the coffee grounds and use a feeler gauge between the fins from 3 O clock to 9.

    every time the heat exchanger is cleaned ( yearly ) a combustion analysis MUST be done.

    You  have a bad fan motor - replace it.

    When you have the over or under speed fault it is usually a bad fan. It can be the board but it is usually the fan.
  • Mike M
    Mike M Member Posts: 34
    contaminants

    I think its something getting in the air intake like grass clippings when cutting the grass or the dryer vent pumping lint outside (it can travel a good distance). The just might be dead crispy critter BEES. And never forget about the Kids factor....
  • Mike M
    Mike M Member Posts: 34
    contaminants

    I think its something getting in the air intake like grass clippings when cutting the grass or the dryer vent pumping lint outside (it can travel a good distance). The just might be dead crispy critter BEES. And never forget about the Kids factor....
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,858
    edited November 2013
    I think your boiler hasn't been serviced properly...

    For many years.



    You may have had people in your mechanical room, but based on evidence presented, no one actually did a fire side cleaning.



    The accumulation of debris in the combustion chamber is typical and expected. Not cleaning the heat exchanger compounds the problem by burning this debris into the exchanger and making clean up much tougher.



    I've never seen a combustion chamber and heat exchanger that didn't have that stuff in it.



    I suspect your fan is fine. Clean up the heat exchanger, fire, retest and see if your problems go away. I have seen the burner sock get plugged up with crud and cause all kinds of issues with the fireside. Not being able to properly breath, the blower is cavitating, not moving any air, and consequently showing high RPMs for the applied voltage and expected RPMs. These machines are much smarter than we give them credit for...



    At a minimum, the inside of your boiler should be inspected and cleaned once every two years.



    BTW, your vent/ combustion air terminations do NOT meet the manufacturers requirements, and can negatively affect the operation of the appliance as others have said. Ignoring that problem will cause your electronic to go away due to exposure to acidic moisture (cross contamination, regurgitation of exhaust products).



    ME

    There was an error rendering this rich post.

  • Leisole2
    Leisole2 Member Posts: 23
    Current status

    We did a full cleaning of the boiler (after the fact). We put the whole system back together again, but the fan still did not work. We have a fan currently on order, should be here early this week. Before they started to work on the termination ends I got another picture. They were definitely not correct.
  • Leisole2
    Leisole2 Member Posts: 23
    Current status

    We did a full cleaning of the boiler (after the fact). We put the whole system back together again, but the fan still did not work. We have a fan currently on order, should be here early this week. Before they started to work on the termination ends I got another picture. They were definitely not correct.
  • Leisole2
    Leisole2 Member Posts: 23
    I wasn't there

    I wasn't there for the cleanings. I assumed he knew what he was doing. Now I'm worried he hasn't done the combustion analysis in years.
  • Ironman
    Ironman Member Posts: 7,555
    Please...

    Tell us that these pics are up side down.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • Steve Whitbeck
    Steve Whitbeck Member Posts: 669
    edited November 2013
    fan

    It is not anything getting into the intake pipe that is causing the build up. This build up is normal for this type of boiler. Flue gasses getting drawn back into the intake pipe Will destroy the blower and the control module.

    A dirty heat exchanger can not cause a fan over or under speed fault.

    The control sets a certain RPM and the fan has to run within a range of that rpm. If it doesn't then you get the fault. The control is not looking for a given airflow. It is only looking for a set rpm. A plugged heat exchanger will cause lower air flow and thus lower gas flow. The control will continue to raise the rpm up to the maximum as the heat exchanger gets dirtier. Same principal as an ECM blower speeding up as the filter gets dirtier.

    The plugged heat exchanger will result in a higher rpm than a clean one.
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