Jotul Sebago direct vent problem

[Ronny]

Hello everyone and a happy holiday season to all. It has been over a month since my last posting so rather that pick up that thread I thought it best to start anew. My stove is vented through a west facing wall into a 14 inch snorkel and runs fine as long as the prevailing west wind isn't blowing. We have had two good storms within the last month which gave me an opportunity to experiment with damper settings etc. When the stove was running, at any setting and the wind gusted the flame would "ghost" (as DAKSY described it) so following his suggestion, I briefly removed the glass from the front and found that even with the flame at the highest setting a cold outside breeze could be felt over it which actually blew the flame exhaust out into my living room so…after quickly replacing the glass, I think I may have discovered the problem. Since we have a steady 7" of water gas pressure (that is about .25 or 1/4 PSI I think) that remains steady with all our gas appliances running, furnace, HW heater, clothes dryer, kitchen stove, and the Jotul, It seems like the gusting wind pressurizes the fire-box and prevents the gas from emerging from the burner so main flame and pilot-poof!-go out, starved not for air but for gas.
If I am correct there seems to be no solution except removing the pesky snorkel and venting the stove up and out the roof.
What think you? Ronny

 

[DAKSY]

Hello everyone and a happy holiday season to all. It has been over a month since my last posting so rather that pick up that thread I thought it best to start anew. My stove is vented through a west facing wall into a 14 inch snorkel and runs fine as long as the prevailing west wind isn't blowing. We have had two good storms within the last month which gave me an opportunity to experiment with damper settings etc. When the stove was running, at any setting and the wind gusted the flame would "ghost" (as DAKSY described it) so following his suggestion, I briefly removed the glass from the front and found that even with the flame at the highest setting a cold outside breeze could be felt over it which actually blew the flame exhaust out into my living room so…after quickly replacing the glass, I think I may have discovered the problem. Since we have a steady 7" of water gas pressure (that is about .25 or 1/4 PSI I think) that remains steady with all our gas appliances running, furnace, HW heater, clothes dryer, kitchen stove, and the Jotul, It seems like the gusting wind pressurizes the fire-box and prevents the gas from emerging from the burner so main flame and pilot-poof!-go out, starved not for air but for gas.
If I am correct there seems to be no solution except removing the pesky snorkel and venting the stove up and out the roof.
What think you? Ronny

So when you removed the glass, was there an issue with the flames burning ok?
I mean othere than exhausting the combustion byproducts into your home, the burner stayed lit, correct?
I doubt that it's a pressure issue. Ghosting is caused by insufficient O2 - period.
The gas will continue to flow as long as there's a pilot flame to actuate the thermocouple & thermopile.
You're getting so much wind that it's blowing the exhaust gasses back in thru the fresh air intake & because
you've already burned the oxygen that was in that airstream, the burner & pilot have none left to combine with
the gas to keep the combustion process going.
Somehow, you have to divert the exhaust away from the intake.
Vertical venting may be the only answer

 

[Ronny]

Hello and thank you for your reply. Instead of writing "ghosting" I should have said it just went out. I have spent a lot of time sitting on the floor in front of this stove watching it and I have seen it seemingly starved for air when the flame lifted in a kind of lazy way off the burner and went out along with the pilot. When the wind was gusting during my 'experiment' the flame burned as long as the glass was out (with the exhaust and cold air blowing into the room) but as soon as I put the glass back in, it went quickly out. That's what led me to think the wind pressure in the fire-box stopped the gas flowing.
Ronny

 

[DAKSY]

Hello and thank you for your reply. Instead of writing "ghosting" I should have said it just went out. I have spent a lot of time sitting on the floor in front of this stove watching it and I have seen it seemingly starved for air when the flame lifted in a kind of lazy way off the burner and went out along with the pilot. When the wind was gusting during my 'experiment' the flame burned as long as the glass was out (with the exhaust and cold air blowing into the room) but as soon as I put the glass back in, it went quickly out. That's what led me to think the wind pressure in the fire-box stopped the gas flowing.
Ronny

It's definitely a combustion air problem. You proved that when it kept going with the glass off.
The only times flames lift off the burner is when they are "searching" for O2.
If there's no O2 NOTHING will burn...

Can you post a pic of the snorkel cap?

 

[Ronny]

OK, will do, I have some I took before the snow. Ronny

 

[DAKSY]

Whose snorkel cap is that? Doesn't look like a Duravent...

 

[Ronny]

Hi, It's a Duravent 14" snorkel with a Duravent 'wind guard' over both the intake and exhaust ends. They would offer no further advice other than selling me the two wind guards, as the fella said on the phone "no field alterations authorized". Ronny

 

[DAKSY]

OK...What is your Air Inlet Restrictor set at?
It MUST be set at fully OPEN for ANY snorkel termination
(per figure 6 page 9)...

 

[Ronny]

Air inlet restrictor is set fully open, exhaust restrictor is set fully open. Ronny

 

[DAKSY]

Have you tried closing the exhaust restrictor?
Looks to me like it should be either in the "A" or
"B" position, based on the short length of horizontal run
(figure 9 page 10)...

 

[Ronny]

No, It is the way the dealers tech left it after the initial set up. I will try that tomorrow though if the wind is still blowing otherwise I'll wait for the next storm and let you know. Now I have a problem with the snow on the roof drifted up to the furnace intake, being sucked in and melting in the burner box, then dripping down on the ID fan and other electrical parts. I rigged up a baffle to drain it off till morning. (Maybe Florida isn't such a bad idea—just kidding). Ronny

 

[Ronny]

Hello,
Well the snow storm has moved on and the wind moderated quite a bit. The furnace air intake stopped dripping but I found that the heat from the Jotul stove pilot light had melted the snow which was falling on the snorkel. The melt-water dripped down and refroze almost completely filling the inside of the wind guard and blocking about 85% of the exhaust outlet. After that was cleared I re-lit the stove with the exhaust outlet damper in the minimum, mid and full open positions and trying both lo-fire and hi-fire gas valve settings but the stove would not stay lit for more that a very few minutes. So I guess I will live with it until I can afford to remove the snorkel and patch the hole in the side of my house and install a vertical–coaxial vent through the roof terminating above the peak of the roof.

I don't understand how the vertical–coaxial vent system works though, if the air intake and exhaust are at the same level how is a natural draft achieved with no difference in elevation between the two and without the benefit of an FD or ID fan?
Ronny

 

[DAKSY]

The vertical co-axial system has the exhaust gases exiting at the
upper portion of the larger cylinder.
The intake air gets in thru the smaller diameter under the cylinder.
The exhaust gases should go up upon exiting.
The cooler intake air should never intermix based on their being cooler...

Still seems to me that you have a vent issue that should be correctable, but without
physically seeing it in action, I hafta bail on this one I guess...
We tried....

The ONLY other thing that could be happening is that there's a mismatch in the
inner (exhaust) 4" pipe, allowing the spent gases to re-enter the firebox thru the intake...

 

[Ronny]

Hello,
Well I thank you for your efforts and time trying, I appreciate it. Do you have an opinion about which company makes the best vertical exhaust system components? Ronny

 

[DAKSY]

Hello,
Well I thank you for your efforts and time trying, I appreciate it. Do you have an opinion about which company makes the best vertical exhaust system components? Ronny

Simpson Dura-vent makes as good a DV product as anyone.
Now that you're having issues with their horizontal stuff,
I'm not sure how to convince you, tho...

 

[Ronny]

Yeah, I couldn't say that I'm impressed by their 14" snorkel but who knows, if it had been installed on the leeward side of the house it might have worked fine? Thanks for the tip, I will look up their vertical stuff and start planning for the future. Thank you again for your time and please have a happy holiday season and a prosperous new year! Ronny

 

[DAKSY]

Hey, Ronny!
I just came across a Jotul bulletinn that gives notification (From Oct 09!)
that Simpson DuraVent Pro Vent series Snorkel & Sconce caps are
not recommended for venting the Jotul Gas stoves.
There appear to be some performance issues & Jotul & Simpson
are working to resolve the issues.
There are other snorkel caps out there that ARE approved & maybe
you can try swapping snorkels for an approved version, before you
tear apart your home to install the vertical system...

 

[Ronny]

Hello DAKSY,

Thank you for thinking of me and for the update. I will surely investigate other manufacturers snorkels. But I have been experimenting, trying to solve the problem on my own and the results are encouraging so far. The Simpson wind guards are about one square foot to each of their three sides so I cut two pieces of aluminum flashing the same size, curled it and stuffed it up inside each wind guard where it sprang open against the insides of the guards and that held it in place. Then I closed the exhaust damper of the stove to the mid position, slot B, and lit er off! With a mild wind, and about 15-20 mph gusts, the stove ran very nicely for the first time which was encouraging. Now I am eager to see how it will perform with a stronger wind. I will keep you posted. Regards, Ronny

 

[Ronny]

Hello Daksy,

Hope you have had a warm winter. The "field modification" I mentioned I was going to try in my last post worked very well all winter. that is adding a round section of aluminum flashing inside of each Duravent wind guard. We had at least three good wind storms with gusts of 40—50 MPH on the stove side of the house and once or twice the burner flame of the stove sort of hesitated for a heartbeat but KEPT BURNING! So I think my problem is solved without any additional investment like the through the roof chimney I was considering.
I feel much better now and I thank you (all) for your interest and advice. Regards, Ronny

 

[DAKSY]

Hey, Ronny.
Glad you figured it out without incurring any major expense.
Sometimes the bubble gum & bailing wire techniques work as
well as the major cash outlays.
While your system probably wouldn't stand up to a qualified
inspector's scrutiny, you seem to have made it work.
Keep an eye on the glass & your siding.
Any carbon (soot) build-up will let you know if there's a problem.
Also, make sure your CO detectors are working, for safety's sake.
See ya next winter!