The Wall
Forum / THE MAIN WALL / Knight boiler problems
  • Post a Reply to this Thread

    Knight boiler problems (63 Posts)

  • Leisole Leisole @ 8:37 PM
    Contact this user

    Knight boiler problems

    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?
  • bld999 bld999 @ 9:02 PM
    Contact this user

    Prev. servicings

    How much debris was in it the first two servicings?
  • Leisole2 Leisole2 @ 10:38 PM
    Contact this user

    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 @ 11:51 PM
    Contact this user

    Combustion analysis?

    Was a combustion analysis done initially or at the servicing?
    Do you have the results?
    Carl 
  • Leisole2 Leisole2 @ 11:59 PM
    Contact this user

    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.
  • Eastman Eastman @ 11:57 PM
    Contact this user

    where

    could that physically come from?  Is it actually rust?  Or some kind of combustion byproduct?
  • Zman Zman @ 11:59 PM
    Contact this user

    Good question..

    Where is the air intake/exhaust  located. Do you have a picture?
    Carl
  • Leisole2 Leisole2 @ 12:13 AM
    Contact this user

    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 @ 12:20 AM
    Contact this user

    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
  • Leisole2 Leisole2 @ 12:32 AM
    Contact this user

    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 @ 12:54 AM
    Contact this user

    that is bad

    but do you still have some of the material you found in the boiler?
  • Leisole2 Leisole2 @ 1:00 AM
    Contact this user

    Still have the junk

    I did not vacuum it out so I could show it to another pro.
  • Eastman Eastman @ 2:26 AM
    Contact this user

    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.
    This post was edited by an admin on October 30, 2013 2:41 AM.
  • bld999 bld999 @ 10:15 AM
    Contact this user

    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"?
  • Eastman Eastman @ 12:20 PM
    Contact this user

    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.
  • Nom_Deplume Nom_Deplume @ 11:00 AM
    Contact this user

    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 @ 11:42 AM
    Contact this user

    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.
    This post was edited by an admin on October 30, 2013 11:48 AM.
  • Stekay Stekay @ 6:22 PM
    Contact this user

    Further discussion

    Here's the thread from the "Gas Heating" forum.
    http://www.heatinghelp.com/forum-thread/127942/Strange-residue-in-Giannoni-heat-exchanger
  • Leisole2 Leisole2 @ 8:32 AM
    Contact this user

    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.
  • Paul Pollets Paul Pollets @ 6:57 PM
    Contact this user

    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!!
  • Leisole2 Leisole2 @ 8:35 AM
    Contact this user

    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.
  • Nom_Deplume Nom_Deplume @ 11:25 PM
    Contact this user

    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
  • Leisole2 Leisole2 @ 8:49 AM
    Contact this user

    Thread

    Thanks for the link. I was looking around for something like that.
  • Bob Bona Bob Bona @ 7:55 AM
    Contact this user

    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 @ 8:47 AM
    Contact this user

    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.
  • Canucker Canucker @ 10:10 AM
    Contact this user

    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.
  • Eric Eric @ 6:06 AM
    Contact this user

    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.
  • Leisole2 Leisole2 @ 11:20 AM
    Contact this user

    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 @ 11:20 AM
    Contact this user

    Oops, double post

    Nothing to see here...
    This post was edited by an admin on November 1, 2013 11:22 AM.
  • ced48 ced48 @ 11:17 AM
    Contact this user

    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?
  • Eastman Eastman @ 12:39 AM
    Contact this user

    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 @ 6:05 PM
    Contact this user

    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.
    This post was edited by an admin on November 2, 2013 6:12 PM.
  • Leisole2 Leisole2 @ 6:09 PM
    Contact this user

    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.
  • Steve Whitbeck Steve Whitbeck @ 8:44 PM
    Contact this user

    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 @ 10:20 PM
    Contact this user

    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 @ 9:11 AM
    Contact this user

    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
    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
    This post was edited by an admin on November 3, 2013 9:14 AM.
  • Leisole2 Leisole2 @ 6:05 PM
    Contact this user

    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.
  • Ironman Ironman @ 6:23 PM
    Contact this user

    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.
  • Leisole2 Leisole2 @ 7:44 PM
    Contact this user

    Yes.

    I did them off my phone and they flip for some bloody reason.
  • Ironman Ironman @ 10:02 AM
    Contact this user

    Cleaning

    As others have pointed out, please realize that a proper cleaning involves removing all the debris between the sections. As Steve mentioned, a feeler gauge or an old credit card work well. You've got to get out everything in the crevices.

    It should also be confirmed that there is proper flow through the water side of the heat ex. and there's no scaling.

    If your issue(s) aren't corrected, you're headed for a heat exchanger failure soon.

    Please post a pic or two of the burner.
    Bob Boan



    You can choose to do what you want, but you cannot choose the consequences.
    This post was edited by an admin on November 4, 2013 10:05 AM.
  • Leisole2 Leisole2 @ 11:44 AM
    Contact this user

    Cleaning

    I will post a few pics tonight with hopefully a fairly detailed look throughout the system. I need to take the front plate off and find my snake cam.
  • Leisole2 Leisole2 @ 11:56 PM
    Contact this user

    Pics of blower, burner, HX

    I've posted some extra pics of the blower, burner, HX and exhaust as requested
  • Ironman Ironman @ 8:58 AM
    Contact this user

    Burner

    From what I'm able to see, it sure looks like that burner is plugged in several places. That would causes the blower to over-speed in order to compensate.

    I think you need a new burner.
    Bob Boan



    You can choose to do what you want, but you cannot choose the consequences.
  • Leisole2 Leisole2 @ 4:51 PM
    Contact this user

    Could I take the burner out and test it

    Could I disassemble the air arm, remove the burner unit, unhook the ignition and test it, or am I asking for trouble?

    The parts and labor have now added up nearly to the cost of the boiler!
    This post was edited by an admin on November 5, 2013 4:52 PM.
  • Ironman Ironman @ 6:19 PM
    Contact this user

    No...

    You need to replace the burner if it's as plugged as it appears in the photo.You may find that you don't need the blower after doing that. Then you could return the blower you ordered if it's not been installed.

    I may have missed it due to the length of this thread, but where's your tech? Does he really understand how to service this, or any other mod/con? If we can see these problems through the pics you've posted and from the info you've given, why hasn't he when he's been on site?
    Bob Boan



    You can choose to do what you want, but you cannot choose the consequences.
  • Leisole2 Leisole2 @ 10:13 PM
    Contact this user

    I'm not sure he is a part of this site.

    I never asked. I'll ask him when comes back.
  • Ironman Ironman @ 9:22 AM
    Contact this user

    Site

    As in your job site, your house, etc. Not this website. Though, that would do him a world of good to come hear on a long term basis.
    Bob Boan



    You can choose to do what you want, but you cannot choose the consequences.
  • Leisole2 Leisole2 @ 6:05 PM
    Contact this user

    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.
  • Mike M Mike M @ 10:20 PM
    Contact this user

    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....
  • Steve Whitbeck Steve Whitbeck @ 7:07 PM
    Contact this user

    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.
    This post was edited by an admin on November 3, 2013 9:17 PM.
  • Zman Zman @ 11:48 AM
    Contact this user

    Be sure...

    Be sure to inspect the venturi and all the parts on the intake side of the boiler. Cross contamination can destroy all sorts of things.
    Carl
  • solradman solradman @ 3:20 PM
    Contact this user

    check the burner

    Check the burner cylinder holes to see if they are clogged.  The cylinder has dozens of small holes around it.  They are pinhole size and may need cleaning also.  I've seen as much as half of them clogged and this will affect the air flow.
  • Mike Mike @ 8:35 PM
    Contact this user

    blower wheel

    A little recap, you have clean the heat exchanger, checked the vent pipes, redid the outside vents. and
    Still having problems.
    What does the blower wheel look like on the inducer motor? If you did or do have discharge air being suck in, the blower wheel will not look good. Do you have a picture of the impeller? you may not realize how bad it looks till you get the new one and compare.
  • Steve Whitbeck Steve Whitbeck @ 10:16 PM
    Contact this user

    wheel

    The new blower will come with the wheel - it is a complete unit.
  • Gordy Gordy @ 7:34 PM
    Contact this user

    Great thread

    On why yo,u need to maintain a mod/con properly!
  • Ironman Ironman @ 9:25 AM
    Contact this user

    Amen...

    To that, Gordy.
    Bob Boan



    You can choose to do what you want, but you cannot choose the consequences.
  • Kenny Greene Kenny Greene @ 6:41 PM
    Contact this user

    Fan Hi Speed lockout

    I had the same problem with a KBN399. Called tech support and they advised me that it could be the board or the blower. No way to diagnose unless you bought their special tool.
    I work on boilers and commercial water heaters from all manufacturers and this is the only one that requires a special tool to diagnose a blower circuit.
    Not sure what is going on at Lochinvar, but they certainly are not the company that they used to be.
    While the tool was not expensive, I could not wait as the boiler is the source for domestic hot water year round.
    Installed a new board and blower. Problem solved temporarily. Upon start up, the heat exchanger leaks when cold.
    I will address this in another post.
    Will never purchase or recommend Lochinvar.
  • Leisole2 Leisole2 @ 1:39 AM
    Contact this user

    Current Status

    The new fan has been installed and the system is working. I was not here for it, but the new pro checked out the burner and said it was fine and the cleaning I did was pretty thorough, but he says the burner and HX may not last nearly as long as it should due to the junk in the HX and on the burner. I watched it through several cycles and it seems to be performing fairly close to our previous nominal state.
  • Mark Eatherton Mark Eatherton @ 1:14 PM
    Contact this user

    When you serviced this combustion chamber,,,

    Did you run a credit card in between the gaps of the heat exchanger? Or did you just vacuum out as much of the crap as you could? Did you use CLR or something to clean it as well? Did you power flush/vacuum out the condensate disposal system?

    There is a LOT more to doing a full and proper service to these things than meets the eye. If it were properly maintained on a yearly basis, you wouldn't have to resort to such drastic tactics (credit cards, flushing etc) but when they go that long, the problem goes much deeper than you can see with your eyes.

    ME
    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
  • Leisole2 Leisole2 @ 2:54 PM
    Contact this user

    Cleaning

    I used a silicon knife and followed all of the gaps twice; once after the second vacuuming and one after the flush. I used only water under hand pump pressurization for the flush. I also rechecked the whole system using an inspection cam i have, inlcuding the condensate line. Lastly, I vacuumed one more time with a nylon ended slot brush.

    I hope I was fairly thorough, but I am more cognizant now of the potential problems.

    Thanks!
  • bld999 bld999 @ 3:20 PM
    Contact this user

    Clr

    As Mark pointed out, using CLR or similar helps cut the hardened crud. A spraybottle of Lime-away is about $6 from a drugstore and is enough to clean 2-3 small boilers.

    What type of camera did you use?
  • Leisole2 Leisole2 @ 4:44 PM
    Contact this user

    Cleaning

    Sorry I didn't get back to you. I had to go out of town for a few weeks. I have a 16' waterproof USB camera I use for plumbing issues. I will go back and clean it again on a warm day with CLR.

    The boiler is nominal as of now, but the reroute of the vents did not go well. We had high winds last week, and I came home to a downed tree limb that knocked off the new vent.

    We will be repairing that this week.
  • smklin smklin @ 12:08 PM
    Contact this user

    low fan lock out

    Had a problem on a 399 .Called tech support they told me to replace the fan. So i played with it a little bit it seamed like the fan was partly ceased . Took it apart and replaced a bearing in the fan housing. I picked up for like a buck .Put it back together . Have not had a problem sense . I own the boiler.  .
     .
  •  
Post a Reply to this Thread