Dirty Glass - Airwash not working?

[wendell]

I just replaced my glass yesterday after a breakage (so I'm starting with a clean slate as I've had the problem I'm going to describe below before the glass broke) and am finally ready to admit there is something not quite right about my stove.

When I was at the dealer yesterday picking up some gasket cement, I was watching one of their Morso stoves burn and was amazed at how clean the glass was and was told they only clean the glass once a week. I have seen many similar comments here and then if their glass does get dirty, they just let the fire heat up and everything burns off. I know that most things need to be taken with a grain of salt but my stove glass needs to be cleaned every day and just as an experiment, I've really been watching it and for the first two hours after I fired it back up the glass stayed spotless but then quickly started developing a slight whitish haze (except for the top 1-2"). I didn't clean it this morning and although you can still see through the glass the haze is getting pretty thick. Since the Morso only allows 450 degrees on the flue 8" above the stove it is pretty hard to get it cranked up too much to see if things will burn off. I did just have a really nice secondary burn going with the flame hitting the glass really well and nothing seemed to change.

As far as I can tell, the draft is good. The only time I get any smoke in the house if I get my hand in the wrong spot and interrupt the airflow and get a quick puff out. The glass never gets black (unless a log falls against the glass and that will burn off as soon as the log is gone). As you can see from my avatar, I have a 90 above the stove and then about 15 degrees as the pipe enters the chimney (interior) and then the T going up from the basement about 35 feet to the top of the pipe. So I do have a slight violation of the 2 90 degree bend rule.

I would love to get up on the roof to check out the pipe (as the problem does seem to be a little worse as the winter as gone on) but with the snow don't feel like risking the 30 foot trip to the ground.

What I find curious is that 1" at the top of the glass that is staying pretty clean. It makes me wonder if somehow the airwash is blocked and that is what is keeping the glass from staying clean. I'm burning elm that is around 17% (but oddly the elm seems to do this more than the maple i was burning that was over 25%)

I hope that is enough information (and possibly WAY too much).

Thanks!!

 

[Dix]

Does the Morso use the airwash system with a baffle in the front of the stove, with a front control (slider) ?


Could be that you're air flow is blocked with ash.

 

[savageactor7]

Wendall it sounds to me that you're burning OK.

We burn pretty hot but our glass will still get clearish white haze on it every 24 hrs. Just about every morning before reloading I'll shovel out some ashes and clean the glass with a paper towel and bottled water.

Even when it's dirty you can still look through it but I like it clean clean...and it only takes a minute or so. Sure a hot fire will clean the black soot off so you can look inside and see what going on ...but it's not what I would call clean.

Our QF has a air wash system too but 'clean' is another ambiguous term ...like seasoned.

ps I meant to give you props the other day when you bought 2 replacement glasses... I've been doing the same thing around here for years. LOL

 

[SWNH]

My Oslo also has that white haze constantly. The stove hasn't been cool enough to clean the glass since....sometime in December.

 

[wendell]

Wendall it sounds to me that you're burning OK.

Thanks for the vote of confidence and yes, it does seem to burn OK and I am still amazed how much heat such a little stove can put out but to me watching the fire is as important as the heat that is produced. So when I see a stove from the same manufacturer with crystal clear glass after hours of burning, I want that!

ps I meant to give you props the other day when you bought 2 replacement glasses... I've been doing the same thing around here for years. LOL

Thanks again but the problem with buying two is when you ignore their disclaimer saying they are accurate to 1/16th of an inch AND you don't take out the old glass (because you don't want cold air blowing down your flue while you are waiting for the new glass to come) and when you measure the opening you don't realize that the brackets are inset another 16th from the outside of the opening.

All I can say is thank goodness for Dremel!

 

[EatenByLimestone]

Any sizzle when you burn a split?


Matt

 

[wendell]

Any sizzle when you burn a split? Matt

Of course not! Seriously, most of the pieces I have split and tested are around 17%

 

[Hogwildz]

If its whitish, its normal. If its black, its wet wood or not burning hot enough.
How close are the splits from the glass when your loading & burning? Mine does the same thing. The only way to keep this from happening here, is to load shorter splits that are about 3" away from the glass.
I assume you are burning front to back? I do, and the ends of the splits off gassing against the glass also causes the white haze, along with fly ash. Unless of course, I keep the splits like I said, about 3" away from the glass.
It wipes right off with a wrung out wet soft rag.

 

[wendell]

I have been keeping wood at least 3" away the last day but it doesn't seem to make any difference. I actually burn side to side most of the time because 13" is short enough. I do front to back on the 8-10" stuff I get from the huge rounds from the trunks.

 

[ashpanannie]

Does the Morso use the airwash system with a baffle in the front of the stove, with a front control (slider) ?


Could be that you're air flow is blocked with ash.

This is a very good suggestion, and I really think it was my initial problem with dirty glass. I frequently had some density of haze on my glass that did not seem to want to self-clean, so I found myself cleaning glass almost every day. When I learned about paying attention to that baffle area and keeping the ash shoveled back, it really made such a difference and now I have very clear, self-cleaning glass most all of the time.

The only other thing I altered a bit was giving more time for my fire to cook with full air before cutting it back, and then doing that gradually with a quarter slide at a time.

 

[wendell]

The primary air control is a lever in the front which I believe moves the control in the back of the stove. I see i am in quite the minority here as a Morso owner but can anybody tell me where this baffle is that may be blocked with ash?

 

[savageactor7]

^I'm pretty sure they're talking about an upside down 'V' shaped aileron right in the front middle of the stove.

It directs air over the glass...when I rake the hot coals over the V you can watch the coals melt away and turn to ash...it's a very quick process that directs the primary air up over the front of the glass.

It looks like this carrot ^

 

[Mr.M2]

Using shorter splits and starting fires with a top-down burn has helped to keep my glass relatively clean the whole season.

 

[stoveguy2esw]

you are just a bit lazy in the draw department , the fact hat the top of the glass is clean but dirtys up below suggests that you are either backin the stove down too soon in the char stage , or simply arent developing as much draft as the store flue is. try running a bit longer before slowing the stove and see if that cleans you up , if not you have somthing slowing down the draft of the flue.

bear in mind i didnt build this stove so i dont have a dog in the fight , but ive seen similar things with our units and virtually all the time it ends up being draft associated. are you in a newer home? if so crack a window and observe , if it stays cleaner longer its negative pressure, an OAK would clean it right up.

too large a flue cross section can do this as well, what are the flue dimentions?

 

[Todd]

Does that horizontal run in your stove pipe have a rise in it as it goes towards the wall or is it just straight and level? Also try and check your chimney cap for clogging.