Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Oil boiler - rear refractory cracked, needs replacement

jdbs3 Member Posts: 27

My first time to this site; I've already found it very useful. Found an article on preventative measures that should be taken when one has an oiler boiler with a cracked rear refractory.

i've done some work on my boiler, but stick to things I feel comfortable with, or that I can do with a handy person who has experience in both plumbing and electric. Together, we have installed a new smart controller, new shut-off valves, new back flow preventer, etc. What I will not get into is cleaning/tuning the system.

Last year, my oil tech said the rear refractory was starting to show cracks and recommended it get replaced at the next system tune-up. This work fits with what I feel capable of doing, with a little bit of Q&A.

I've read the instructions for installing a new Lynn #1072 replacement combustion chamber kit, watched a youtube video of a tech installing one on a Weil-McLain boiler (mine is a WG-04), and am ready to do this myself with the assistance of the handyman I'll hire.

The only question I currently have is what to disconnect to open the chamber door, and what to do when reconnecting this part. Referencing the attached picture, I would:

1. Turn off the oil valve coming into the oil filter cartridge on the left side of the oil burner.
2. Remove the screws holding the oil filter cartridge to the burner, and pull the cartridge assembly away from the burner.
3. Open the chamber door – one bolt.
4. Remove and replace the rear refractory.
5. Close and bolt the chamber door.
6. Reattach the oil filter cartridge assembly.
7. Turn on the oil valve coming into the oil filter cartridge.


- Am I correct that this is all that needs to be done to access the rear refractory?

- By removing the oil filter cartridge, might I be introducing air to the system, so I should partially tighten the 4 screws, then open the oil valve, let it flow for a few seconds to purge any air, then tighten the screws?

My thanks in advance for your input.


  • mgdesrochers
    mgdesrochers Member Posts: 20
    If you don't feel comfortable with cleaning / tuning I would recommend that you hire a professional to replace the combustion chamber.
    New chambers cure once the system is fired for a period of time (usually 15 minutes). Once the chamber is cured you HAVE to perform a complete combustion analysis to ensure that the system is still burning clean.
    The actual work isn't difficult but the combustion analysis must be done.
    EBEBRATT-Ed Member Posts: 13,165
    take a good look at the old chamber a few minor cracks don't mean much as it is a wet base boiler. If all the refractory is "in place" I wouldn't worry about a few cracks.

    If pieces of refractory have fallen off or is deteriorating then replace the chamber.

    sounds like your procedure is correct. You may or may not need to disconnect or un plug the electrical connections.

    The condition of the burner end cone and blast tube that extends into the boiler should be checked.

    It would be smart to clean the boiler, burner and do a combustion check at the same time
    HVACNUT Member Posts: 4,873
    Your Lynn chamber kit will also come with a blanket, board for the front plate and rope.
    Not as easy as it seems. You should have a soot vac, stiff wire brush and a large flat head screwdriver to brush and scrape excess. Actual installation is cake. It's removal and prep that makes it a job.
    My real reason for commenting here is the QB180 burner. Do you know they haven't been manufactured for years now and parts are hard to come by. They have a static pressure design flaw causing the burner to periodically hiccup causing incomplete combustion. I always recommend replacement whenever I come across one.
  • rick in Alaska
    rick in Alaska Member Posts: 1,396
    Personally, I would take the fuel pump off rather than disconnecting the fuel line and going that route. Less chance of fuel spillage and introducing air back in. All you would have to do is pop the clip off the fuel pump solenoid ( the round black piece on the fuel pump with the electrical line going to it) and then take off the two bolts holding the fuel pump on. Slide the pump out of the way, disconnect the electrical connector going to the burner, take off the cover nut, and you are good to go.
    Pull out the fuel pump coupler while you have the fuel pump off and make sure it is not stripped out, or close to it. Good time to replace if necessary.
    Make sure when you are changing out the refractory that you wear a good air mask. The refractory material is considered cancer causing, so use all cautions.
    As the others have said, if the refractory does not have holes in it, and is still sitting flush to the back wall, I would leave it alone.
  • jdbs3
    jdbs3 Member Posts: 27

    RE: take a good look at the old chamber a few minor cracks don't mean much as it is a wet base boiler. If all the refractory is "in place" I wouldn't worry about a few cracks.

    See the attached photo taken through the peep hole. The refractory is in place. I believe the cracks you see have been there for a few years. Not sure I would call them minor though.

    The rest of the combustion chamber parts on the inside of the door are all in good shape - no cracks.

    The picture makes it appera that where the major cracks are, that sections of the refractory are ready to fall forward. However, shining a flashlight at it, it does not appear to be so, as in the picture.

    What are your thoughts, given the picture, on the need to replace it?

    HVACNUT Member Posts: 4,873
    Yes, that target wall should be replaced. Looks like some impingement going on which is a symptom of the QB180. I would invest in a Riello and junk that burner.
    The QB180, manufactured by Wayne is specific to the Weil McLain WGO/WTGO. It was a partnership Weil McLain would like to forget.
  • STEVEusaPA
    STEVEusaPA Member Posts: 5,983
    I don't think you should do the job yourself. You're not saving much money and you will need a full combustion analysis. As others stated you should give the heat exchanger a proper cleaning. So bring in the tech and tell him to bring the chamber kit.
    For a while, you could lean on WM for a new Beckett burner if you had the QB. Don't know if that is still the case.
    EBEBRATT-Ed Member Posts: 13,165
    Yes, new chamber, cleaning and combustion testing. Never worked on that burner so I will defer to others. Most have a low opinion of it
  • rick in Alaska
    rick in Alaska Member Posts: 1,396
    I guess I am one of the few that don't have much issue with it. The fuel line connection has a tendency to loosen up and make it hard to get the fuel line off, but I haven't had any problems making it burn clean.
    Now the NX burner of the Blue Angel..............