Exhaust Air Attacking Internal Flame

[Jay Z]

We had the worst winds since I moved into my farmhouse last night. I have been running my pellet furnace for over a two months without any problems. My exhaust termination is just the elbow type. Last night the flame was getting reduced and bounced around. Is this because of the strong winds pushing back into the exhaust termination? Was looking into another type of termination cap. I did clean my stove this morning and seems much better. I went through all motors and piping just to make sure nothing was plugged. I clean my furnace on a weekly basis so not a maintenance concern.

 

[Harvey Schneider]

We had the worst winds since I moved into my farmhouse last night. I have been running my pellet furnace for over a two months without any problems. My exhaust termination is just the elbow type. Last night the flame was getting reduced and bounced around. Is this because of the strong winds pushing back into the exhaust termination? Was looking into another type of termination cap. I did clean my stove this morning and seems much better. I went through all motors and piping just to make sure nothing was plugged. I clean my furnace on a weekly basis so not a maintenance concern.

If you had an OAK on the same side of the building as the vent, the wind pressure would not be able to push air back through the vent since both inlet and outlet would see the same pressure.

 

[Jay Z]

I was always concerned about not having an OAK. My furnace guy was going on the old place is drafty and plenty to draw from. I also think a better termination cap and OAK should help out. I am sitting on a hill with full hits from South and West winds.

 

[Harvey Schneider]

I was always concerned about not having an OAK. My furnace guy was going on the old place is drafty and plenty to draw from. I also think a better termination cap and OAK should help out. I am sitting on a hill with full hits from South and West winds.

I don't think that the cap will make much difference if the OAK and vent are near each other. If there is no pressure difference there can be no air movement. If the OAK and vent are not subjected to the same pressures due to objects obstructing the wind there can still be back flow.

 

[Bioburner]

How far away from the house is the termination? Moved the Bixby's out another foot and most problems went away per another users recommendation.

 

[Harvey Schneider]

How far away from the house is the termination? Moved the Bixby's out another foot and most problems went away per another users recommendation.

That makes sense. The static pressure from the wind increases as it approaches a solid obstacle. Further from the wall results in less pressure. Less pressure, less backflow.

 

[Madcodger]

I was always concerned about not having an OAK. My furnace guy was going on the old place is drafty and plenty to draw from. I also think a better termination cap and OAK should help out. I am sitting on a hill with full hits from South and West winds.

Furnace guys should be required to either pass a certification exam or at the very least prove they paid attention in physics class. Most apparently did neither.

 

[Jay Z]

My exhaust extends straight out about 20" with the termination elbow pointed opposite the wind. Its a Duravent Pro Horizontal style to create a "Venturi effect. Guess the claim is this style of vent creates more pull of exhaust.

 

[Harvey Schneider]

My exhaust extends straight out about 20" with the termination elbow pointed opposite the wind. Its a Duravent Pro Horizontal style to create a "Venturi effect. Guess the claim is this style of vent creates more pull of exhaust.

Anything designed to create a venturi effect is going to be influenced by prevailing winds. That means that if the stove is optimally tuned in still air it will not be when the wind is blowing (and vice versa). Is that the source of your variability?