venting out old woodstove pipe?

[Cory S]

Like mentioned, both a woodstove and pellet stove are both fuel burning appliances. Both need venting, and both utilize up draft. If anything, a tight pipe seal technically would be more important on a wood stove anyway. Woodstoves can emit far more harmful gasses, yet because of updrafts, slight air leaks in stove pipe usually cause no ill effects (Unless your burning wet smoldering wood, and it smolders out with a cold chimney etc)

Using "pellet vent" pipe is usually more emphasized on new installations where there is no previous chimney/stove piping to begin with. I went over this with my Harman dealer/installers for a good hour. There were a few advantages to using your existing 6" stove pipe, and almost zero negatives. The only negative was clearance to combustibles stays the same with your pre-existing stove pipe obviously. Adapting your current stovepipe to the pellet stove is less than 1/2 the cost, requires far less cleaning because of the volume the 6" pipe has, and IMHO looks far better than 3-4" pellet vent pipe.. So....with MY particular installation, it works out perfect. In most new pellet stove installations, then yes, going to pellet vent is the "correct" venting to use, and I agree 100%. I really do not think there's many people who do "NEW" pellet stove installs with stove pipe.

 

[bholler]

If anything, a tight pipe seal technically would be more important on a wood stove anyway.

Not true at all because with a wood stove air will be pulled in not pushed out.

Woodstoves can emit far more harmful gasses,

Also not true both are burning wood and create the exact same byproducts.

almost zero negatives

Unless a joint is not sealed right and smoke or co leaks into the house. I would consider that a major negative.

 

[Cory S]

Not true at all because with a wood stove air will be pulled in not pushed out.


Also not true both are burning wood and create the exact same byproducts.


Unless a joint is not sealed right and smoke or co leaks into the house. I would consider that a major negative.

The lower efficiency and off gassing from a woodstove burning a less refined product with 18-20+% MC, will indeed have a higher % of caustic byproducts.

Stove piping is not sealed, and almost impossible for CO to come from pipe joints when there's even just a minimal draft. I have tested CO detectors with stove pipes through out the years.

"Not true at all because with a wood stove air will be pulled in not pushed out"
OK and? ^^^^^ So you think having a warm updraft chimney is NOT drawing on the exhaust of a pellet stove??

 

[bholler]

The lower efficiency and off gassing from a woodstove burning a less refined product with 18-20+% MC, will indeed have a higher % of caustic byproducts.

true as long as the pellet stove is working right. i have seen some pellet vents that were pretty nasty and i have seen pellet vents that have had chimney fires in them as well. You are burning the same thing so the potential is there with either type.

OK and? ^^^^^ So you think having a warm updraft chimney is NOT drawing on the exhaust of a pellet stove??

The difference is if there is no natural draft in a wood stove the fire will go out. With a pellet stove the blower will keep the fire going and there will be positive pressure in the pipe. That is why they say you need to seal the joints right?

 

[Cory S]

true as long as the pellet stove is working right. i have seen some pellet vents that were pretty nasty and i have seen pellet vents that have had chimney fires in them as well. You are burning the same thing so the potential is there with either type.



The difference is if there is no natural draft in a wood stove the fire will go out. With a pellet stove the blower will keep the fire going and there will be positive pressure in the pipe. That is why they say you need to seal the joints right?

Correct, but with the exhaust blower, there's airflow through the piping anyway. So in either case, there's should be little to no stagnant harmful gasses in the exhaust run. Unless there's a combustion exhaust failure, and pellets smolder in the stove. In that case, there could be leaks virtually anywhere over time.

Both situations require either major user failure, or appliance failure of the worst possible scenario.

All my point is in this debate, is that it's not "wrong" per say, to use a combination of pellet vent/stove pipe as long as a proper and thoughtful installation is followed.

 

[bholler]

All my point is in this debate, is that it's not "wrong" per say, to use a combination of pellet vent/stove pipe as long as a proper and thoughtful installation is followed.

I agree it is not wrong but it is far from the best option.

Correct, but with the exhaust blower, there's airflow through the piping anyway. So in either case, there's should be little to no stagnant harmful gasses in the exhaust run. Unless there's a combustion exhaust failure, and pellets smolder in the stove. In that case, there could be leaks virtually anywhere over time.

Yes and when that blower is running it can be pushing smoke and fumes out of any unsealed joints right? And wood smoke can contain co and other potentially harmful substances at any point in the burning process correct?
Like i said it can be done safely and i work on units hooked up like this. But i absolutely will not install one that way

 

[Harman Lover 007]

As I said in my first statement, I was not looking to debate this AGAIN. Cory, if you truly believe that a pellet stove works on the "draft" principle, the same as a wood stove, you are dead wrong...no pun intended.

 

[daffonce]

I agree wood stove venting the pressure inside pipe is negative (in reference to the room) thus any unsealed joint will draw room air into the pipe, thus no co leak issue with unsealed pipe. On a pellet stove vent, the pipe is after the exhaust blower thus the pressure in the pipe is positive (referenced to the room). Thus if there are any unsealed portion of the pipe exhaust will exit the vent into the room. The exhaust can potentially have co, possibly allowing unsafe co levels to build in the house. The positive vs negative pressure makes all the difference in the world. It is unsafe to run unsealed vent with a positive pressure appliance. No question about it, dont care what the dealer said.

 

[Edsson]

Question. Installation of a new pellet stove into an existing woodstove bricked chimney, does the double walled vent insert need to go all the way to the roof,~25 ft. or just above the stove.

 

[Harman Lover 007]

Question. Installation of a new pellet stove into an existing woodstove bricked chimney, does the double walled vent insert need to go all the way to the roof,~25 ft. or just above the stove.

In some cases, it depends on the brand of stove. But most installs in existing chimneys allow the use of a flexible pipe/liner to go the vertical run to the top terminating with a cap.

 

[Bioburner]

Sometimes trying to stub the vent into a existing chimney won't work because the draft won't be created because of the stoves low heat

 

[Edsson]

Thanks, I am installing a Quad E2. After long research I decided it was the best for me. Replacing a Hearthstone I woodstove after 30 years, and heating 2000 sq ft.

 

[Bioburner]

Good luck, hope the stove does well by you.