smoke

This topic contains 10 replies, has 4 voices, and was last updated by  ksb 3 months ago.

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  • #3897

    ksb
    Participant

    I have a masonry heater that has functioned well for ten years. Occasionally due to weather patterns we get smoke coming back into the house and opening a door usually solves this. This year I am constantly getting smoke coming back into the house. The fire starts fine then dies back and spews smoke out of the face plate into the house. If i open the face plate doors the fire flames – when I close them the fire dies and smokes – any advice would be appreciated

    #3898

    ksb
    Participant

    Update – I cleaned out the base channels and took out a lot of soot so I thought I was gold. Sparked up the fire exact same result. It minus 20 and I am sitting in a smoke filled house with  the windows open! Any thoughts would be greatly appreciated.

    #3899

    norbert
    Forum Administrator

    Here is a note on cleaning the Heatkit contraflow heater, which has a specific spot that needs to be checked for soot buildup:
    http://heatkit.com/html/cleaning.htm

    If it is a cold start issue, ie the heater is cold and the weather perhaps has changed, the following discussion may help. Note, the client in the discussion had a Heatkit, and the cold start issue he thought he was having turned out to be the cleaning issue, above, which I had asked him the check first, but which he didn’t:

    ————–quoted text follows——————————

    Hi xxxxxx:

    If the heater has been functioning normally, it is unlikely that it is an issue due to blockage. This page has information on how to check:
    http://heatkit.com/html/cleaning.htm

    Otherwise, the situation you describe is fairly normal, in some houses. For the reasons you describe.

    We have the same issue in our own house, due to some kind of house depressurization that I am trying to track down.

    Fortunately, there is a very easy workaround: I have a self igniting propane torch

    Inline image 1that I use with a short camping type propane cylinder, for stability.

    The minute you notice a false start and smoking, you crack open one of the clean out doors near the floor, the one closest to the chimney.

    Aim the torch in there, and it will power up the chimney and reverse the flow almost instantly and prevent smoking.

    Depending on how severe the draft problem is, you may need to put heat into it for several minutes, hence the short cylinder for a stable setup.

    This is a 100% workaround. I keep the torch handy, and very occasionally have to use it during unusual startup conditions.

    In terms of tracking down the pressure issue, it can vary and we can discuss it in more detail and try to do some diagnostics.

    I was also able to figure out right away that if I cracked a nearby exterior house door, the temperature reversal in the chimney stops, and the temperature starts climbing again. This is a 100% diagnostic for house depressurization, since opening the door provides enough makeup air to satisfy the negative pressure. In our case, we have a tall house which acts like a chimney itself, being filled with a column of warm air. If you have any leaks in the upper part of your house envelope, this will cause a negative pressure in the lower part of the house.

    —————–end of quoted text—————————–
    The basic diagnostic procedure is as follows:
    – verify that the fuel (firewood) is 20% moisture or less and the correct size and stacked according to the stove’s written operating instructions.
    – verify that the stove’s channels are clean and that there are no blockages.
    – follow the cold start precautions (keep a torch hand, as per above)
    Norbert
    Attachments:
    #3901

    norbert
    Forum Administrator

    Here is a note on cleaning the Heatkit contraflow heater, which has a specific spot that needs to be checked for soot buildup:
    http://heatkit.com/html/cleaning.htm

    If it is a cold start issue, ie the heater is cold and the weather perhaps has changed, the following discussion may help. Note, the client in the discussion had a Heatkit, and the cold start issue he thought he was having turned out to be the cleaning issue, above, which I had asked him the check first, but which he didn’t:

    ————–quoted text follows——————————

    Hi xxxxxx:

    If the heater has been functioning normally, it is unlikely that it is an issue due to blockage. This page has information on how to check:
    http://heatkit.com/html/cleaning.htm

    Otherwise, the situation you describe is fairly normal, in some houses. For the reasons you describe.

    We have the same issue in our own house, due to some kind of house depressurization that I am trying to track down.

    Fortunately, there is a very easy workaround: I have a self igniting propane torch

    Inline image 1that I use with a short camping type propane cylinder, for stability.

    The minute you notice a false start and smoking, you crack open one of the clean out doors near the floor, the one closest to the chimney.

    Aim the torch in there, and it will power up the chimney and reverse the flow almost instantly and prevent smoking.

    Depending on how severe the draft problem is, you may need to put heat into it for several minutes, hence the short cylinder for a stable setup.

    This is a 100% workaround. I keep the torch handy, and very occasionally have to use it during unusual startup conditions.

    In terms of tracking down the pressure issue, it can vary and we can discuss it in more detail and try to do some diagnostics.

    I was also able to figure out right away that if I cracked a nearby exterior house door, the temperature reversal in the chimney stops, and the temperature starts climbing again. This is a 100% diagnostic for house depressurization, since opening the door provides enough makeup air to satisfy the negative pressure. In our case, we have a tall house which acts like a chimney itself, being filled with a column of warm air. If you have any leaks in the upper part of your house envelope, this will cause a negative pressure in the lower part of the house.

    —————–end of quoted text—————————–
    The basic diagnostic procedure is as follows:
    – verify that the fuel (firewood) is 20% moisture or less and the correct size and stacked according to the stove’s written operating instructions.
    – verify that the stove’s channels are clean and that there are no blockages.
    – follow the cold start precautions (keep a torch handy, as per above)
    Norbert
    Attachments:
    #3904

    ksb
    Participant

    For whatever reason the torch work around is not working – there are three clean outs at the back – I am using the middle one – I cannot prop a torch next to it as the clean out doors are not hinged, so I have to hold the door slightly open to use the torch. The house is the same house the chimney worked fine in for ten years – so I am not sure why we would suddenly have a depressurization issue (although it is a cathedral ceiling) . I now am wondering about the wood since we had such a wet spring maybe its moisture content is too high – I got from the same person I always get it from and it is usually very good and dry.   One other thought we have a heat recovery ventilation system – could this be a problem?

    #3906

    David Wilcox
    Participant

    The HRV should help your problem ,sounds like your wood is dry on the surface but wet in the center causing a good  start then cooking off the steam after a few minutes and that steam does not like to go up .Get a moister meter split the wood and test.  Dave  Wilcox

    #3970

    ksb
    Participant

    Thanks Dave – I thought it might be the wood as well but last night to test I put a few pieces of barn board I had in a shed for the last three years and same result – really at my wits end at this point

    #3998

    yellowcat
    Participant

    While the heater is cold, what if you very carefully connected a leaf blower with a substantial MPH and CFM rating to one of the clean outs. Maybe use some foam rubber or even expanding foam sealant to be even more safe. Then have someone rev that baby up ! It could be a very exciting event to witness both inside the house and out ! Call the neighbors first ! Ideally this could be like back flushing a radiator and you would clear out any buildup that might be blocking a channel. In the worst case you might end up being labeled as eccentric or some similar term by all your neighbors or anyone else who might be a witness to this ! Do you have a good shop vac, just in case you try this and something does go wrong ?

    #3999

    norbert
    Forum Administrator

    Here’s an update on the client’s smoking situation:

    He has  a HeatKit heater, and I worked with him via email doing various diagnostics, starting with the most common stuff.

    In the end, it turned out that the mason who installed the heater did not install the sliding chimney damper properly, and it had been stuck (in the assumed open position) since the heater was new.

    The client had a chimney sweep out for the second time, and I advised the sweep to check the damper first. Turns out, this is what it was, and the heater is now functioning good as new ………….. N.

     

     

    #4001

    yellowcat
    Participant

    Thanks for the update Norbert,

    A damper in the wrong position is kinda anticlimactic for such a serious problem. The leaf blower back flush experiment could have made for a very entertaining and possibly educational video !

    #4002

    ksb
    Participant

    Many thanks to Norbert and Yaro for the help getting this fixed.  As Norbert said the twist in the story was the damper which was basically locked in the same position (open) for 10 years and the heater worked fine. So I had kind of eliminated that as the problem because I didn’t believe it could move. But once we were able to look at it with a mirror it was clear the damper had closed down more somehow(a mystery as to how) and we now have it fully open – still hard to close it and open it but it can be done  – fire is burning great

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