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[Smeegs]

I have had a problem with a build up of creosote/ tar build up in my fan air box . I have resealed the fire box door gasket along with the reaction chamber door gasket as well so no air leaks are possible. But when I inspect the air box above the fan there seems to be a lot of heavy smoke when the OPTI 250 is at an idle. All of the flapper valves seem to be operating correctly and surfaces have been cleaned and inspected regularly with each cleaning. Is this normal? If not , how do I correct this issue?
Smeegs

[slimjim]

Some smoke coming back into the airbox when the cover is off is normal, smoke will always search for fresh air, moisture or creosote is a tell tale sign of an air leak, how old is your unit?

[cowman]

not meaning to hijack your post Smeegs, but we also have OPTI 250 and have the same issue. our unit is 2 years old.

[slimjim]

OK guys are you seeing this more when is brutally cold out or all the time, if it is more prevelant in extreme cold then some of it may be caused by cold air coming into a warm airbox and then cooling off the airbox, you might try adding some more insulation to the back of the boiler if it is that serious.

[willowbk]

I guess I can jump on the wagon also, my stove has a born on date of may 2012, this is my first season w/ owf.
I've have been running for 3 months and have all the same issues since day one. slimjim has sent me the new gasket which I replaced.
the brown staining from smoke has gotten better in rear airbox, but it can change within a day or so.  my creosote on the inside I feel is excessive, it runs down from the steel and gets on bricks.  it has actually bowed out the metal strapping in between the two, in spots.  my wood is a bit green, but all readings are under 20%.
I've tried bumping up temps to 195 w/ less than 8pt dif.  so sounds like we have some common ailment that we are doing wrong.
it does seem like the staining in the airbox could be from leaving doors open to long like when loading or cleaning. I started taking cover off during cleaning to avoid the smoke build up in the box.   and I wont go into the nozzle topic since mine is shot after 2 months.

[coolidge]

 The nozzle are an easy fix with off the shelf firebrick, a little cutting and fitting and your done. I have been using this method for three years now. once they get worn you can just turn the brick around ( if not broke) and have another square edge.

[jreimer]

OK guys are you seeing this more when is brutally cold out or all the time, if it is more prevelant in extreme cold then some of it may be caused by cold air coming into a warm airbox and then cooling off the airbox, you might try adding some more insulation to the back of the boiler if it is that serious.

Does anyone have a good idea of how to clean the airbox of creosote?  In my climate there is just no way of keeping the airbox warm enough that you don't get some creosote baked onto the airbox.  Mine has a good layer cemented onto the inside of the airbox and it's going to start interfering with the mechanisms inside of there.

[martyinmi]

I have had a problem with a build up of creosote/ tar build up in my fan air box . I have resealed the fire box door gasket along with the reaction chamber door gasket as well so no air leaks are possible. But when I inspect the air box above the fan there seems to be a lot of heavy smoke when the OPTI 250 is at an idle. All of the flapper valves seem to be operating correctly and surfaces have been cleaned and inspected regularly with each cleaning. Is this normal? If not , how do I correct this issue?
Smeegs

Make sure that the round disc in the fan box is seated completely on the pipe that supplies air from the fan.
Mine did what you are referring to and I CAREFULLY bent the flat strap downward an eighth or quarter inch and it solved the problem.
I find that the majority of the creosote in the airbox comes from using splits that are too small and sometimes too dry. While the boiler is cycling, too much gas is released from the wood causing an improper fuel/air ratio, which causes "huffing". You'll hear a "woooof" sound, and if you look at the back of your boiler you'll see a puff of smoke that comes out from the fan housing. Rounds about 6" - 8" or so seem to be ideal- for me anyway. I split 9" and over. I only catch mine "huffing" when I put too many wrist sized (3 inchers) in at once.

[Sprinter]

Never heard that one before.....too dry of wood. 90% of creosote problems is wet wood , sustained low water temps and or a really bad air leak.  Yet I've seen some guys burn some unseasoned wood and their fire box is pretty clean, bigger units too.

I've always considered P&M one of the best, sorry to hear these problems.

[martyinmi]

Sprinter, google "firewood too dry". There used to be several articles on the web about firewood that gets too dry.
That's why the "industry standard" so to speak for well seasoned wood has been and is still a point or two plus or minus of 20%.

P&M's are one of the best. We work together to make them better on this forum.

[jreimer]

I'll agree with Marty. P&M's are some of the best and it's the knowledgeable folks on this forum that help them meet their true potential.

We ask questions and tweak them because we care!   

I agree with the dry wood huffing. To me it sounds like it's sneezing!

[slimjim]

Never heard that one before.....too dry of wood. 90% of creosote problems is wet wood , sustained low water temps and or a really bad air leak.  Yet I've seen some guys burn some unseasoned wood and their fire box is pretty clean, bigger units too.

I've always considered P&M one of the best, sorry to hear these problems.

      I think you are wrong on this one sprinter, 90% of creostote problems is not green wood but instead a large portion of the problem is in the heat load, there are a lot of variables in wood burning and double that when you are using a gasser, I think that we have an excellant record and continue to solve any problems that arise one at a time, if moisture is the problem then why can I use green oak at the multiple shows that I do all over the northeast and not have problems with creosote,Answer= I keep a heavy and steady heat load on it, the creosote is created in the off cycle. Caution folks please do not do this at home as it, is not good for the stove, with exhaust temps as low as we are getting, the moisture may condense in the tubes.

[Smeegs]

I do have a heavy creosote build up in my air box, all the hardware is coated and a 1/4 inch build up on the floor of the air box. I have cleaned all the moving parts and checked for good contact on the damper valves ensuring that the best seal is obtained with what is there, would adding a rubber gasket surface to the inlet air damper off the fan help? I even ran a bead of hi-temp silicone around the outside of the air box to stop any leakage. I never had a problem with this last season , but this year is different. The heat load is more than adequate , heating 3600 sq' home , 2 car garage, domestic hot water and a 2400 sq' work shop. the stove keeps up fine in minus 20 -30 C. with generally only two feedings of seasoned oak morning and night. I am very happy with heating it does, I just want to solve the creosote problem in the air box. Is there a best method to clean out the creosote from the air box with out using solvents while the furnace is in use?

[slimjim]

Smeegs do you have the new silicone door gaskets on both front doors, if not call Brian and order them, the moisture is from an air leak and rope door gaskets are the big culprit, as far as cleaning it, Spray Nine makes a creosote cleaner for glass that works well, most good hardware stores will have it on the shelf