Our fireplace was WETT Certified installed. Everything done right and approved by the insurance company. The unit has its own air intake and a chimney that goes straight up. The problem is [was] that the after gases do not burn off properly as this little video shows. At the time of this blog post we have had the stove for 6 years, its always done this. Some call it whuffing, or wuffing, or huffing. [Edit note Sep 05 2013: To clarify, not every time but its gotten worse the last couple years.]
EDIT: To get a quick, clear idea of what we are experiencing, scroll down to March 3 and view the video. In particular, the puffs of smoke at the 18 secs mark, and the explosions at the 53 secs mark.
Also, check at the bottom of this blog post… before the comment section… for updates to our history with this stove.
This is a video of our Harman wood stove.
Dec 20 2011
Seems the Harman company found our video online yesterday and said they would call us. We didn’t get a call, we received an email:
“The video you posted on YouTube shows a classic case of a blocked airway.”
They provided some tips on wood drying, blocking airways etc. They then refered us to the local dealer.
Dec 21 2011
We emailed the local dealer yesterday, waiting to see if they reply. All day yesterday we were very mindful of the fire, it had exploded once yesterday. Last evening we went to bed and the damper was shut with the draft set to half open. Mid way through the night we woke up with the heavy acrid smell of smoke in the air. That GD thing was exploding again. We had to turn the air exchanger on to max to clear out the house.
Dec 22 2011
Definitely a draft issue. Pipes smoke when door open. Here is a short video:
Correspondences and incidents that followed afterwards:
This morning I thoroughly check all parts and the air intake. Everything seems normal. Sparked up a fire with a few splits. Once it was going, added a few small split birch 3″ diameter split in half and let that catch before adding some larger pieces. Sure enough, BOOM. GD! Once thing for sure, this past month is the most occurances we’ve had with the explosions.
Local dealer called yesterday and we discussed the issue. He says a draft test should be performed. Waiting now for their dealer to call and see if we can diagnose the problem.
Local dealer called this morning. They spoke with Haram who indicated the problem might be ‘over drafting’. They require a draft test needs to be done, if the gauge shows over .08 then there is overdraft situation. The dealer also spoke about environmental conditions such as negative pressure in the house; bathroom fan going, dryer vent going, stove exhaust fan going.
We rarely turn on the bathroom fan. We do not use a dryer, we have one, just don’t use it. And our overhead stove fan exhausts back into the room, no external vent. Dealer talked about outdoor conditions; barometric pressure drops, location of fireplace exhaust vent and wind that passes by the location causing unique situation. The thing is, the wind is typically calm when these explosive events occur.
Dealer says air is being pushed into the firebox, I think its being pulled in but I’m open to explore all solutions and possibilities.
Local dealer called, who said they’d have company call. No one has called. Since then the stove is performing a little better, still get the occasional whuffing (mini explosions).
Dec 23 2011
Most bad experience with this Harman wood stove. Uploaded a video to youtube.
This clip is 26 min long. We’re having a lot of draft issues with the stove. It performed just fine during the day, burning around 500-600F. Using birch and maple. At about 10:30 PM, it started to act up. Nothing changed in the environment (temps, winds). We had cleared the door lass the day before but its covered in soot again over the top half so its a bit difficult to see everything that is going on.
0:00 to 06:42- Flames billowed and plummed. Next, http://www.youtube.com/watch?v=ibeQsoiK58c
06:42 – I opened the damper to try and clear out the stove and clear the glass.
07:19 – I closed the damper
07:43 – I put the draft to about 3/4 open
12:00 – flames start to ball up again
18:00 – I had put in text that says “Finally..it calmed down.” but that’s not correct. I might have to upload the vid again.
19:00 – Bigger plumes of gas, I got closer to the stove. Big balls of flames.
20:00 – Decided to open the damper and draft. Opened the door. Smoke coming from the black pipes. Closed the door, smoke still coming out. Fire raging in the box.
21:10 – Stove wide open, window open nearby. Smoke still coming out of the black pipe.
21:35 – Closed the damper. Smoke STOPS coming out of the black pipe. Weird!
Only way the fire will stay in control is damper closed and draft wide open.
From that point on, I slowly closed down on the draft until it was 1/4 open. Flames slowed and coals cooled enough to say it was safe. Went to bed.
Also posted this video on youtube on Dec 23 2011. Harman Oakwood Fireplace smoking chimney problems
Well, we’re at our wits end on this stove. We did not run a fire all day today after last nights incident. But, after supper, things start to cool off. So I cleaned the glass, and sparked up a small fire. See this video.
Draft and damper open to get the fire started.
And lo’ and behold, smoke coming from joints in the chimney. So, what the hell? Fire not hot enough to push the smoke up the chimney? How the hell else is a fire suppose to be started?
NO MORE FIRES until someone can tell me what’s wrong.
Mar 03 2012
Another video of the Harmon Oakwood stove going BOOM again
Another snapshot from today. The explosions prior to the camera rolling set off the fire alarm in the house and lifted that top trap door a full 3 inches. My dear wife, sitting 5 ft away nearly had a heart attack from fright when it exploded… not once… but twice.
Mar 04 2012
Chimney Spin Cap installation, Excel model
Mar 03 2012 – Having to take care of the poor draft issue on the Harman Oakwood fireplace, we were recommended by local dealer to install one of those spinning wind caps. This is our video of that installation. This is an Excel model cap made in Canada by ICC Industrial Chimney Company Inc.
Mar 26 2012 – Update: Well the stove is still exploding. The chimney cap has helped a lot but the ‘wuffing’ of gases and explosions in the firebox of this Harman fireplace (Oakmwood model) is still occurring.
May 08 2012 – Update: Gases still are not clearing properly. Some wuffing still occurring.
A user, t0rr3sfamily, on Youtube posted the following “My friend has this problem (same stove) when windy outside. I say it’s a draft problem rather than stove problem.” at http://www.youtube.com/watch?v=ibeQsoiK58c Other youtube users posted similar comments on this video.
Sep 25 2013
Youtube user, Justin Veysey, posted the following comment at http://www.youtube.com/watch?v=OufT_JWCvkM
I just found your video and corresponding posts. Thank-god I found what you wrote. I have the exact same stove and the exact same problems! I have owned this piece of crap stove for a year and I have tried everything to alleviate the issue. I just lit a fire last night for the first time and again I experienced the huffing/puffing with this stove. So frustrating., Smoke in the house! Can we talk about how you solved the issue? Thanks.
Some people were commenting about the temp gauge we are using on the stove. Pictures are below. This is the one from last year. Before we do start fires this year the unit will be replaced. I don’t know if that’s necessary or not, but there’s always a bend in the probe due to heat I guess. So I always start with a new one.
September 30, 2013
Today I had the local refrigeration repair at the house, John Besaw is his name. He promptly diagnosed the problem with our fridge and we moved onto the subject of burning wood. He asked me how much wood I was burning and I began to tell him the story of the difficulty we have with this Harmon Oakwood. Having burned wood all his life, he was curious. John enjoys puzzles apparently because he took the time to listen to me and ask questions. He narrowed down his focus to the secondary burn, and the stove’s inability to burn off the excess gases. We went the stove as he wanted to know how the stove functioned, air flow, etc. We focused on the back of the stove where we assumed there must be a secondary chamber.
We took off the heat shield (4 bolts) and there remained 5 more stove screws required an allen key (hex head). I went out to the garage and retrieved the tools and took them off, which required a little bit of effort. As we removed the rear plate, a “chamber” which looked to be made of the same liner material as inside the firebox, was attached to the back plate, we slowly pulled it all out.
What we discovered was quite honestly… shocking. The chamber was almost full of creosote and ash.
Come to find out the “chamber” was stuck to the back plate and we were able to separate the two.
The amount of material inside the chamber was incredible.
And still there’s more…
Looking at this chamber I came to the conclusion that all those small little holes, “ports” I call them, probably are meant to have air or gasses flow through them. So I gently placed a piece of copper wire in a couple holes but they came to a stop about an inch inside. As I inserted the wire towards the holes in the center, the wire went through. So, I came to the assumption that all the holes should be through and through. I poked the wire through each of them, most met with a little bit of resistance., meaning they were plugged with soot/creosote.
Now that the secondary chamber is cleared out, time to bring it back to the stove for reinsertion. I used the shop vaccum to clean out the right side to compare a before and after in this chamber area.
[Dec 05 2023 – It must be noted now, in this historical account, that for this image below, notice the shoe brick and how it is installed. This picture was taken in 2013. That show brick is installed upside down. That elongated gap in the show brick should be facing down. I only learned in October 2023… 10 years later… of this. Once the shoe brick was installed correctly, the stove has been burning ok.]
This entire area is not accessible unless you take this route and do the work. No where in the stove’s owners manual do it say anything about cleaning this part of the stove, or even mentioning the necessity to clear this area.
The last step was to put the back plate on the stove and the heat shield. On thing I did notice was the back wall of this secondary chamber has a inward bulge (dip) in its surface. I’m guessing its either an intentional part of the design or its a weak spot.
You can clearly see the dip here.
We have yet to start a fire with the stove, now that its thoroughly cleaned out. I’m actually feeling relief and hesitation at the same time. Relief that we found the obvious fire hazard that was existing in this wood stove and a little hesitation with starting a new fire and not knowing how the stove will behave. I’ll guess and say that it will be better performing, but that lingering feeling of a bad, very bad, history with this wood stove will always linger… just like the smoke that blows out from this wood stove when it does back fire.
Time will tell and I’ll be sure to continue updating this conversation as we move forward.
I would like to take this opportunity to especially thank fellow Newfoundlander John Besaw, the refrigeration repair man from Antigonish, for having the curiosity and willingness to take his time to listen and help diagnose the problem. That’s far more help than what I received from the manufacturer.
Apaprently this issue is nothing new with regards to the secondary chamber filling up with material. Here is a discussion I found at Hearth.com (link). That discussion thread is now closed but I started a continuation here.
Oct 01, 2013
This photo is added today to show Justin Veysey what the air intake kit looks like. Its a black piece of metal, pre-bent to fit the underside of the back of the Harman Oakwood stove. You can just see the 4 inch duct which is the intake pipe. You will also see insulation and a black pipe covering over the duct. I did that because that duct is a direct vent to outdoors and that duct pipe gets REALLY COLD in the winter.
Started fire about 30 min ago. Damper open, draft open full. A couple things of note;
there appears to be good draw considering there’s no wind right now
initially I could see flames being pulled into the secondary chamber
in less than 3 min the flue thermometer said it was 450F
about 2 min after that it reach 800F
closed the damper
flame remained active (it used to die out) and cooled back to 400F in about 3 minutes, draft still wide open
Its now about 3 minutes later and the flue therm says 350F.
October 08, 2013
We’ve run a few fires now and the stove is finally working normally. Our only wish throughout all of this experience was that the Harman wood stove manufacturer take a pro-active position in helping us solve the problem. It took the local refrigeration repair man, to whom we are very grateful.
October 21, 2013
Adding this picture of the door glass for the Harman Oakwood wood stove, as part of a conversation below.
November 01 2013
Started a fire this morning. Raining outdoors, winds from the south at 24 km/hr. Barometer at 750 and falling.
Immediately puffs of smoke coming from joints in the chimney. Went outside, spinner cap ok and working, smoke coming out of the chimney. Fire came up to temp, about 600F, but the stove still smoking puffs. House is now full of smoke, waiting for the alarms to go off.
Patrick Dender mentioned about making sure the ports to the air chamber line up.
Cleaning out the stove today, the grate has finally disintergrated. I’ll probably have a local welder make up a new plate from high heat steel.
One of the brick liners broke recently and I did a DIY repair to fix it. You can read more about that here.
Update: October 15, 2023
This week we did a full maintenance of the wood stove. New fire dome and new gaskets for most locations. We also learned a few things along the way. We video recorded the event and you can see it here.
Update: December 5th, 2023
We have been burning in the wood stove pretty much every day since the stove was re-fitted with new parts on Oct 15th, 2023. After learning of the shoe brick not being installed correctly, we resolved that issue. We are burning hardwood short blocks and ends of logs, and 16″ lengths of dry softwood (air dried 2 years). The wood stove has been performing well and throwing good heat. Basically behaving like it’s suppose to. We still use a bungee cord to keep the rear damper door closed, just as a precaution.