Cleaning a Harman Oakwood

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SIERRADMAX

Feeling the Heat
Jan 13, 2011
300
RI
Any tips, procedures to help clean out the secondary burn chamber on my oakwood?
 
First tip, don't worry about cleaning it unless either you are having problems with the stove or it has been three or more years since cleaning, IMHO. While it is worth vacuuming ash out the front of it a few times a season (when the stove is cold, reaching in through the firebox), actually removing the CP -- the combustion package-- increases the risk of damaging it, or of it being put back in place without as good a seal as it originally had.

I used to think it was worth pulling out every year to clean, but no longer believe so. That said, it WILL accumulate ash over the course of several years, which eventually MAY lead to clogging and poor performance. So three years is just my personal recommendation. Some folk have run these stove for many years without ever pulling and cleaning the CP, and some have had problems after only a season or two.

If you do want to clean the CP, remove the back cover of the stove with a hex key. Be sure to pull the cover straight back so you don't damage the fragile CP, which may stick to the cover and be pulled out with it, and is easily cracked. Once the CP is pulled out the back, handle with care. Be extremely careful when vacuuming, as it is quite easy for the suction to pull hunks of the material right off -- one second you think you are cleaning it, and the next thing you know, you're ripping it apart. Each year of use makes it more crumbly and delicate, though recent versions of the CP are a bit sturdier than they used to be.

Make sure the gasket is in good shape and in place when putting the rear cover back on. It is also worth checking to make sure all the bolts for the damper assembly are tight while you have the CP out, and adjusting the damper ramp if necessary. My damper frame was coming loose, and the damper had actually fallen open a few times before I tightened the nuts.
 
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I've had an Oakwood for 10 years, and have followed many of the posts on this site regarding stalls, smoke, cleaning, and CP replacements. I burn it quite a bit, running 24/7 for many weeks most winters. But the past few seasons seemed to be less than great in the performance area. I came here and found the threads mentioned above, so last fall I vacuumed it out pretty good. I taped a 3/8" fuel hose inside the end of my vacuum hose and stuck it over each of the shoe brick vents. I also carefully scooped and vacuumed up and over the shoe brick removing a lot of ash from the CP. It did burn noticeably better last season, but not like it did when new. I ordered a new CP kit (with all gaskets), along with a Harman name brick which broke a couple years back, and a new grate. My grate was warped over an inch and made it difficult to clean. I just got finished with the cleaning and installation. Thanks to the guys posting on here it was a breeze. But I'll add some of my thoughts for those getting ready to clean or repair theirs.
First, I recommend sweeping out as much ash as you can. Then get an allen wrench that fits the rear screws, a 1/2" socket and wrench, and a 7/16" socket. Then you'll remove all the bricks. Start by loosening the bolt clips and turn them up out of your way. Lift out the 2 corner clips. Lift out the 2 clips in the floor. Remove one side brick, and work your way to the other side, brick by brick. Then remove the back of the stove by removing the allen screws and gently pulling the cover off. Mine was not stuck to the CP, but some are. If you are cleaning the CP, lift it up about 1/4" and then pull it straight out the back of the stove (to save the lower gasket material). Then take it outside and shake it gently, rotating it, to remove the ash. I was replacing mine so the gasket didn't matter, but I did empty it for practice. Next, remove the 2 allen screws that hold the secondary (?) rear lower air intake shield in place. Mine was packed full of fine ash. I removed my shoe brick last, and it lifts right out. It sits on a 3/8" gasket rope so there's no reason for it to be stuck. Mine was cracked in two pieces but I decided to use furnace cement to try that before buying a new one. Scoop out the piles of ash that surrounded the CP area. Then have at it with a vacuum, sucking every nook and cranny from the damper to the ash tray. Clean it out so you can find all the bolt heads that were hidden in ash or behind the bricks. I brushed the back cover clean and replaced the gasket there, as well as the shoe brick gasket. I checked every nut and bolt I could find, and was shocked at how many were very loose. I'm certain some of the loose bolts caused air leaks and hurt my performance. Replace everything in reverse order. I did mine in 2 phases since I removed and cleaned everything first. Then ordered parts. Then reassembled it all. Removing everything and cleaning took about 30 minutes. Replacing it all, including adding the new gasket rope and tightening everything, took about the same time.
Thanks everyone for posting previous instructions on this process. I'm looking forward to some cold weather to try it out.
 
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Welcome! Thanks for the detailed post... hope the new CP gives you the performance boost you're looking for. Keep us posted.
 
We had a break in the weather yesterday and I pulled the CP out to clean. Mine was stuck to the rear housign. Some material broke off but I don't think it would impede its performance. To my surprise, there wasn't a lot of ash. However, the two square gaskets at the bottom of the combustion chamber were very brittle and fell apart. I had a fiberglass sheet and made some new gaskets but I would like to order a couple to keep on hand. Is part number 3-44-2500202-4 the part number for those gaskets?
 

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awesome link! Thanks.
 
Anyone have a tip on changing the gasket around the damper door? Looks pretty tight to get my hands in there from the flue opening.
 
Anyone have a tip on changing the gasket around the damper door? Looks pretty tight to get my hands in there from the flue opening.

Since the flue can be switched to either top or rear vent, I assume you would have to remove that entire piece -- as you would if reversing the venting -- in order to have any hope of easily accessing that gasket.

Unless the gasket is badly damaged or degraded in some way, I wouldn't suspect replacing it would have a great impact on how the stove performs.
 
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