pellet furnace exhaust ?

[mhl380]

I have a king 8500 can i hook up the 3 inch to my to my 6 inch exhaust pipe that was for my wood
burner its about 20 foot tall on the outside of the house thanks Rick.

 

[johneh]

The short answer is yes.
But you will find a lot of people on this forum that will say no.
I have had my stove hooked up to a 6 in. insulated chimney for the
length of time I've had he stove . It was approved by the building inspector ,
Fire Department and my Insurance Co. I've never had a problem

 

[Micmann]

Yes it may work, but It also might not. There is a little science behind this question. Some push systems, like pellet exhaust, need a smaller (relatively speaking) diameter pipe to work properly. It works like you blowing air through a straw. The small diameter allows you to easily push all the air in your lungs through and exit out the other end of the straw. Even if the straw was 20' long you could still blow air through it and out the other end. Now try blowing through a 4" pipe. You would have to blow several lungs full to get it to trickle out the other end if you even could get it to move. You will be pushing and pushing all the existing air volume that is just lingering around inside the pipe to barely get it to move. A stove exhaust likes the smaller diameter to push through. Not that smaller is better. There is a fine balance point of pipe size verses flow. If you go to small the flow is constipated and will be restricted. However, to big and the stove needs to push the air coming directly from the stove plus the cubic volume collected in the large pipe. If the pipe is too long the stove will not have the push to vacate the air, Especially heavy cold air. Vehicle exhaust works on the same principle. Too small an exhaust is loss of horsepower. Too big also results in a loss of horsepower. A fine tuned size maximizes horsepower. So yes it could work, and does for some, but an efficient system would be to stay with the 3".

Another thought. Do you need to utilize the old 6"? Could you use the hole going outside and then vent cap it there. Don't know your setup, but you might not need the 20' rise.

 

[SmokeyTheBear]

If you can find the proper adapters and the cross sectional area does not exceed 36 square inches it will generally work for common flue lengths (2 stories) once the length or the cross sectional get larger than that the less likely it will work as needed.

Note work and work as needed are frequently entirely different things.

Needed here means that the exhaust blower can handle the weight of the air in the flue and cause the exhaust to actually exit the flue without creosote condensing out.

All other considerations such as local codes and insurance company underwear tightness issues come into play.

Code where you are is not likely the same as code even one town over let alone in another state or country.

 

[mhl380]

thanks guy's i need to utilize the pipe its only a couple of years old should i come out of the furnace with 3' or 4' to 6'
i also heard that the more 90 'S and 45's that you use it can a draft problem is this true ?
heres my set up i will need a clean out tee and two 45's and one 90 is this too many? if i go with using
the 6' pipe i will need one tee and two 45's

 

[SmokeyTheBear]

thanks guy's i need to utilize the pipe its only a couple of years old should i come out of the furnace with 3' or 4' to 6'
i also heard that the more 90 'S and 45's that you use it can a draft problem is this true ?
heres my set up i will need a clean out tee and two 45's and one 90 is this too many? if i go with using
the 6' pipe i will need one tee and two 45's

You really should look into getting that down to as few elbows as possible.

There should be a section in your manual dealing with venting. The more turns the more the resistance that the exhaust blower needs to overcome however after a certain equivalent vent length the diameter of the vent from the stove onward needs to increase, but once it gets to a certain cross sectional area and weight of air in the flue you will have burn issues as well.

Equivalent length is found using a simple table and adding up the values assigned to each piece of the vent.

 

[mhl380]

Smokey the bear have heard of the king 8500 and is it a good unit or do you know if any other member
has one i got a good deal on it it will go in the basment to replace my wood burner.

 

[SmokeyTheBear]

Smokey the bear have heard of the king 8500 and is it a good unit or do you know if any other member
has one i got a good deal on it it will go in the basment to replace my wood burner.

I haven't heard of that unit. But then since it seems that new numbers are being added every other day, there are likely many units out there that folks haven't heard of. Let me guess, it is another entry in the number soup from USSC.

 

[mhl380]

Yes i guess its a new unit USSC came out with.no reviews on it yet. time will tell when i get it up and running.