DV vent problem

[Ronny]

I have an 18 month old Jotul GF 400 Sebago direct vent gas stove venting through a 45 and about 18 inches straight out the side of my house and into a Simpson Dura-Vent fourteen inch 'Snorkel". The problem is that on windy days the fire will not stay lit. The dealer I bought the stove from is no help, his employees were not able to solve the problem. I called Jotul in Maine and their tech said "Oh those snorkels, I'm sorry we even have them in the catalog". I called Simpson in California and they suggested a wind guard, a perforated aluminum plate which fits around the upper (exhaust) or lower (intake) end of the snorkel and is screwed to the side of the building. I installed it on the top-exhaust end at Simpsons suggestion but the fire still would not stay lit during a strong wind. I bought another wind guard from Simpson and installed it on the lower-intake end but still no improvement. The air intake and exhaust dampers on the stove itself are both wide open at the dealers suggestion but I can't tell if the problem is caused by the wind pulling a vacuum on the intake of the snorkel and starving the fire–it flickers lazily for some seconds before it goes out completely and then even the pilot goes out, or if the wind is blocking the exhaust end and the fire is in either case starving for oxygen. Still thinking the wind is causing the problem I bought a sheet of perforated aluminum from Home Depot and fabricated and installed four 'caps' on the tops and bottoms of the two wind guards to see if that would help but it did not and may even have made the problem worse although it is hard to tell (I called Simpson to see if they thought that might be a solution but all I could get from them was the flat statement–"no field modifications are authorized-period"). Next I am going to remove the 'caps' I fabricated one at a time to see if I can get some idea of what might be the best solution. When the wind is calm the stove works very well.
Thoughts anyone? Ronny

 

[Fsappo]

I have an 18 month old Jotul GF 400 Sebago direct vent gas stove venting through a 45 and about 18 inches straight out the side of my house and into a Simpson Dura-Vent fourteen inch 'Snorkel". The problem is that on windy days the fire will not stay lit. The dealer I bought the stove from is no help, his employees were not able to solve the problem. I called Jotul in Maine and their tech said "Oh those snorkels, I'm sorry we even have them in the catalog". I called Simpson in California and they suggested a wind guard, a perforated aluminum plate which fits around the upper (exhaust) or lower (intake) end of the snorkel and is screwed to the side of the building. I installed it on the top-exhaust end at Simpsons suggestion but the fire still would not stay lit during a strong wind. I bought another wind guard from Simpson and installed it on the lower-intake end but still no improvement. The air intake and exhaust dampers on the stove itself are both wide open at the dealers suggestion but I can't tell if the problem is caused by the wind pulling a vacuum on the intake of the snorkel and starving the fire–it flickers lazily for some seconds before it goes out completely and then even the pilot goes out, or if the wind is blocking the exhaust end and the fire is in either case starving for oxygen. Still thinking the wind is causing the problem I bought a sheet of perforated aluminum from Home Depot and fabricated and installed four 'caps' on the tops and bottoms of the two wind guards to see if that would help but it did not and may even have made the problem worse although it is hard to tell (I called Simpson to see if they thought that might be a solution but all I could get from them was the flat statement–"no field modifications are authorized-period"). Next I am going to remove the 'caps' I fabricated one at a time to see if I can get some idea of what might be the best solution. When the wind is calm the stove works very well.
Thoughts anyone? Ronny

Did you consider trying a 36" snorkel instead? The other option would be to maybe run the pipe up past the roof. When the fire goes out, does the pilot go out as well? If it does, we have installed small wind guards around the pilot lights on some stoves that we made out of sheetmetal.

 

[Ronny]

Thank you for your response. Yeah, I realize that with only a 14" difference between the air intake and exhaust there is not a great deal of difference in atmospheric pressure to create and sustain a draft but the stove does work very well as long as there is no wind to upset that difference. I did suggest the 36" snorkel to the stove dealer but he insisted that it wouldn't make any difference. The pilot does eventually go out too but it does not blow out, rather it is like when you put a glass over a burning candle it just sort of blinks out slowly.
Ronny

 

[Fsappo]

hmmm, slow goes out. We need Daksy in on this thread. He seems to know his stuff on gas appliances. To me, a pilot slowly going out could mean lack of air.

Try PMing Daksy and ask him to take a loot at this thread. Have him answer here so others can learn

 

[DAKSY]

Here I am!
I looked at this one briefly, & wanted to get some of my ducks in a row before responding.
Looking at the installation manual, I agree that the change to the 36" snorkel is worth a shot.
Using the 14" snorkel, there is a max horizontal run of 12" for proper venting.
The OP has exceeded this by nearly 2X.
I also agree that there's intake air issue.
That's the only reason the flames will "ghost" or "lift" off the burner.
The pilot going out is also another indicator of a combustion air problem.
***TESTING PURPOSES ONLY!***
I'd remove the glass to see how your Sebago operates on a windy day.
If it runs fine, then it's DEFINITELY in the design OR assembly of the venting system.
***TESTING DONE! RE-INSTALL THE GLASS!***
I'm still leaning towards the 36" snorkel.
Unfortunately, the 36" unit retails for nearly $500,
but maybe the original seller will take back the 14" in trade?

 

[Fsappo]

Woot, I was almost 50% correct! I'm half a Daksy! Thanks for chiming in, your educating me as well

 

[Ronny]

Thank you very much Daksy! I am glad to read that you too feel insufficient air supply is the cause of the problem. I will definitely try removing the glass from the front of the stove to confirm that, and I thank you also for that excellent suggestion. It may be "biting off my nose to spite my face" as grandma used to say, but neither the dealer I bought the stove from nor his employees are welcome in my home any more, things became far too 'strained' toward the end for that. I don't really want to spend any more money on this project either nor do I want to un-do the installation and reinstall using the 36" snorkel. Maybe next spring when the weather moderates some I will see if it might be practical to raise the height of the exhaust by adapting some pipe or sheet metal to the existing snorkel. An "un-authorized modification". Thank you all again, Ronny

 

[DAKSY]

Hey, Ronny, I can't emphasize enough that the glass removal is for TESTING ONLY.
Do NOT burn it opened up for any longer than a few minutes, or
you'll be committing HARA KIRI!

 

[Ronny]

Ah so! Yes I completely understand. I've had a couple of wood burning stoves and a fireplace and I was raised basking in the glow of a Kerosene stove and later B-vent gas stoves (in a drafty old house). Thanks for the tip though. If anything interesting develops I will post it to this thread. Regards, and have a nice warm holiday season everybody! Ronny