Weird problem

[Dio]

Hi guys. I'm new here.

I'm Dio from the Netherlands.
I hope you guys can help me with this problem. Couldn't find a solution to this on the forum.

I just moved into a new house with a built in fireplace. With experimentation I learned how to make a good fire. Just one weird problem;
It has two glass windows. The front one stays mostly perfectly clean but the back window keeps getting black after a few times. As far as I can tell it is built symmatrical so no idea what causes this.

Any ideas?
Thanks!

 

[jetsam]

Creosote buildup. Fire too cool, most likely culprit is wet wood. Air is probably set way too low for that wood moisture.

Post some photos, including the dataplate that shows the manufacturer/model if possible. Also details about how your wood is seasoned and stored.

That is also normal behavior for stoves that are able to burn very low (and are being burned very low). If that'd the case, just run a hot fire and it will burn off.

Since we don't know anything about your stove, wood, or install- I suggest you inspect and sweep your flue before you continue. You don't want a chimney fire in a new house. You don't know if the flue is even installed safely, and you probably don't know if it has been cleaned recently.

Do not believe what the previous owner told you- it's too important to not look for yourself.

It's not hard- just take photos of everything and people here will be glad to tell you!

 

[EatenByLimestone]

Could also be soot. Pics would help.

 

[kennyp2339]

The front glass prob has more heat creating a air wash effect and the rear glass doesn't have much heat so the smoke creates stain.

 

[Dio]

Thanks for the replies people!
I made some pictures but the glass isn't as dirty as it was since I wiped it a little.

It is a Kalfire fireplace though I don't know the model. I had the chimney cleaned recently.

The wood is from my dad but he doesn't know what kind it is. I assume it's dry as it was stalled outside for more then 2 years. Also he never had problems with dirty glass.

Thanks!

 

[Shmudda]

Thanks for the replies people!
I made some pictures but the glass isn't as dirty as it was since I wiped it a little. View attachment 239911 View attachment 239912 View attachment 239913 View attachment 239914

It is a Kalfire fireplace though I don't know the model. I had the chimney cleaned recently.

The wood is from my dad but he doesn't know what kind it is. I assume it's dry as it was stalled outside for more then 2 years. Also he never had problems with dirty glass.

Thanks!

Dio:

Where is your combustion air fed from? I would expect your clean glass window might be where the combustion air is fed from and the dirty window side is just along for the ride. Just a hunch

Craig

 

[weatherguy]

I see it has a cat, interesting stove/FP.

 

[jetsam]

Ohh, it has glass on two sides of the unit! That's hard to find in the U.S., though people do ask for them.

The air intake is probably on the side that stays clean.

 

[Dio]

The air is coming from below in the middle of the fireplace where the ash pan is located so I don't think one side gets more air. My guess is that maybe the flue is sucking the air too one side more than the other.

 

[armanidog]

The air is coming from below in the middle of the fireplace where the ash pan is located so I don't think one side gets more air. My guess is that maybe the flue is sucking the air too one side more than the other.

I looked at the manual (guessed at the model number), https://kalfire.com/en/fireplaces/product/w105-47t :

"7.4 Keeping clean glass panes
• In the case of an interior with steel slats or a design, the risk of soiling the glass pane is greater than with the standard (skamol) plates.
• The Kalfire W80/52T, W105/47T and W53/50R models, as a result of the relatively small surface skamol plates (which provide the reflection), have a greater chance of dirtying their glass pane.
• Only burn dry wood.
• Open the secondary air regulation completely.
• Open the damper (if present) completely open.
• Ensure the flue has a minimum draught of 12 Pa."

Are you opening the secondary air regulation completely?

 

[jetsam]

The air is coming from below in the middle of the fireplace where the ash pan is located so I don't think one side gets more air. My guess is that maybe the flue is sucking the air too one side more than the other.

Or there is an air leak on the clean side. Check the gaskets!