Pellet furnace to chimney

hello all,

I am in the planning stages for installing a pellet furnace that will be replacing a wood furnace. Currently the 8” wood furnace pipe goes right into the chimney. I am planning to install a 4” liner down the chimney for the pellet furnace. What do I need to make this a clean and safe setup? I assume I need some kind of adapter to get through the chimney block correctly and get the correct 4"size and something at the bottom of the liner to get the 90 degree bend through the chimney wall? I have attached a photo of the current wood furnace setup.

 

hard to tell if there is a clay thimble in place with all the crap gooped all around the pipe.....yea, you'd basically liner it, with a cover plate on top (to carry the weight of the liner), and a tee with snout and cap at the bottom....

 

Try your best of having the least horizontal run as possible and to have a clean-out T as mentioned above
What fuel are you planning to burn?

 

cleanout tees don't work well in chimneys....we cap them....you cant really get to them when they are in the flue.....just be aware they can plug, and be sure to clean often

 

Hi All,

I currently have a pellet stove insert I installed a few years ago (different chimney) so im familiar with the flex liner installation. The chimney the furance would be connected to does have a tile liner already, I would need to check on the thimble. I didn't know if the flex liner would have enough "give" in it to come down, make the turn through the hole in the chimney, and turn back down to the furnace.

-NC454

 

Depends on the interior dimensions of the chimney, I guess. You could always leave the existing thimble if it doesn't impede the bend of the flex, get an 8" -> 4" adapter cap (or a standard 8" stove pipe cap plate & MacGuyver it accordingly) to leave the existing thimble, providing that met code in your locale. ... Might save a few $$$.

 

Attached a screen shot from the installation manual, I’m still not clear on the connection between the liner (green) and the PL venting shown. Would I just use a 90 degree PL pipe here?

 

Out of furnace to a T then up and elbowed to the chimney then elbowed to the liner and up and out is the way to do it?

 

no....the tee is in the flue.....can be difficult to get some liners to bend 90 degrees

 

Ahh
Like you said, a useless T to the rescue
Do without the T at the furnace so you only have one in the vent system? I'm trying to learn the lìner system for future reference

 

Wow.I read this 4 times,and,realize I do imbibe in alcohol,and I find the problem not to be a problem.The chimney has a "clay" liner,and,if it is not too large,he could run the horizontal pipe into the liner,and not need a vertical pipe at all,it depends on the dimensions of the clay liner,same as a pellet stove.What is his furnace flue specifications?Also,putting a 90 inside the chimney is normal.I used to say "most" pellet stoves can be direct vented into an open flue/chimney,but,a pellet furnace has so much more input/output,I really do not see why he could not direct vent this unit into the ceramic chimney.with no 4" pipe to the top of the house/chimney.I could be wrong(have been before) just saying ,we should give proper info,when we know about the burning devise,and the flue/chimney specifications.Yoall can prove me wrong,that is fine.

 

I would see what your local regulations say and if they will allow it I would use a flange'd adapter to connect to the clay flue inlet and not mess with the flex up the inside.

Install a quick flange at the chimney and the stove to allow easy access to clean it.

Butttttttttttttttttttttt..see what the local building dept. says and then keep them happy.


Simple is always the best if you can do it.

Is there any way to direct vent the stove and leave the chimney out of the equation entirely.

Direct vents are a snap to clean... "Stick the leaf blower on the pipe and SUCK"

Tall chimneys are miserable to clean.
All three of our pellet stoves are direct vent right out the wall. 1 has zero bends...1 has a 45 and the last one has a 90
Easy to clean in no time flat.

 

More importantly than the local building department, use the owners manual and see what they recommend (a UL listing and the associated installation manual trumps "code"). The OP iterated he/she was going to use a 4" liner in their first post, and that's how its done.

Yup. basically a useless Tee in the flue, but its the only good way to change direction insider the flue.....you're not gonna get an elbow down there, so, a tee would work....and for those of you who say how the hell are you gonna get a tee in where you cant get an elbow in....they make specific tees for this.

 

Thanks for the input, the unit is a Fahrenheit F50 pellet furnace. I will get a measurement of the clay liner tonight but off hand im guessing its roughly 7x7 or so. If i can just vent into the liner that would be great. About 4 ft down, from where the vent goes into the clay liner is a clean out door I use to clean ash out of the bottom of the chimney.

 

The factory recommendations are certainly GREAT PLACE TO START.
Buttttttttttttttttt, if this is an inspected install the inspector is going to have the final word as to whether he is going to sign off on it.

I have seen myriad SAFE installs that the inspectors would not sign off on, and conversely I have see some real crap that was let slide.

My concern about the long uphill flex pipe is that these pipes collect crap and will need to be cleaned out.

Getting up on the roof to Suck that beast out is never fun...and the safety issue as well.

 

Looks like per the manufacturers installation manual I should have no issue venting into the clay liner as long as its in good shape. I suppose this warrants a chimney inspection.

 

Do not forget your combustion air inlet!.

 

yup, maybe you can avoid a steel liner altogether, just make sure your tiles aren't broken or cracked

 

yea, you've got to clean the liner, fo sho! But also, a smaller diameter keeps your flue gas warmer, allowing it to rise easily....especially it this is an outside chimney, which tend to be cold

 

IMO, a SS liner the correct size for the unit, all the way to the top, with block-off plate and cap is really the best way to go, as LW said.....keeps the pipe hot= better airflow.