8" chimney to pellet vent???

[mascoma]

Hello all,
I have vented my Harman into the 8" metal chimney our wood stove used for the last few years.
This winter some snow/ice came off roof and pulled the top 4-5 ft of the chimney over

So my current venting consists of "
3" pellet vent...
90 at stove
3ft Vert
90 at thimble

into

8" insulated metal
2ft horizontal thru wall
90 outside house
15 ft vertical - terminates 8" above roof line

I have had several chimney guys look at putting the top of the chimney back on and they all say they the old top pipe is bent and unusable, and they can't get any new pipe that would seal up the the old bottom pipe. So they want to replace the whole thing to the tune of $1800 or so.
I know I could switch to just a straight out pellet vent for less, but I would want to run pellet vent as high as the old chimney, then I'm thinking I am back in the $1500 +- range.

This is all a long back story to ask the question of:
Can I put 5 ft of pellet vent (with adapter) on top of the 8" chimney to get it back to original height?
If so would 3" cut it or would I need 4" or 6"

Thanks in advance!

 

[jtakeman]

Now that the 8" is not repairable and too expensive IMHO anyway!

I'd go with all new L-vent But you need to reduce the tees and 90º's to 2 total and with that rise you would also need to move up to 4" to keep the EVL in check. Your probably going to have to repair the existing hole and start from scratch.

If you do the job yourself you can save a buck or 2, But having a contractor install it will be more because of labor costs.

 

[Delta-T]

just curious, why would you want to run the pellet vent to the same height as the old 8" insulated pipe?

 

[save$]

Looks like your 8 chimney is toast. You already have an 3 foot vertical inside, so, unless you have issues with doors and windows being near the vent, why not just go vertical , then horizontal out and stop with that. Very few exhaust for pellet stoves are up above the roof line like you needed for a wood stoves. If you install an OAK, you vent "may" be able to even closer to doors and windows. Your stove manual normally will set these limits. I have the 3 foot vertical inside then horizontal out, and with an OAK. I do need to wash the siding from time to time, but that is the worst of it. This cost could be a couple hundred and is usually a DIY project. Nice thing about this set up is that it is easy to get to when you want to do the leaf blower cleaning. Only caution I have is to make sure you keep drifting snow away from it.

 

[mascoma]

just curious, why would you want to run the pellet vent to the same height as the old 8" insulated pipe?

I know it's probably over kill but every spring I have a bunch of grit/ash on the downwind side of the roof from stove. I'm thinking if the exhaust is lower the gunk may end up finding it's way back into the house instead of going over it.

 

[mascoma]

Looks like your 8 chimney is toast. You already have an 3 foot vertical inside, so, unless you have issues with doors and windows being near the vent, why not just go vertical , then horizontal out and stop with that. Very few exhaust for pellet stoves are up above the roof line like you needed for a wood stoves. If you install an OAK, you vent "may" be able to even closer to doors and windows. Your stove manual normally will set these limits. I have the 3 foot vertical inside then horizontal out, and with an OAK. I do need to wash the siding from time to time, but that is the worst of it. This cost could be a couple hundred and is usually a DIY project. Nice thing about this set up is that it is easy to get to when you want to do the leaf blower cleaning. Only caution I have is to make sure you keep drifting snow away from it.

Probably will end up scrapping the 8" altogether.
Was thinking of going out and then up maybe 5 ft with the vent to save a 90.

 

[save$]

Looks like your 8 chimney is toast. You already have an 3 foot vertical inside, so, unless you have issues with doors and windows being near the vent, why not just go vertical , then horizontal out and stop with that. Very few exhaust for pellet stoves are up above the roof line like you needed for a wood stoves. If you install an OAK, you vent "may" be able to even closer to doors and windows. Your stove manual normally will set these limits. I have the 3 foot vertical inside then horizontal out, and with an OAK. I do need to wash the siding from time to time, but that is the worst of it. This cost could be a couple hundred and is usually a DIY project. Nice thing about this set up is that it is easy to get to when you want to do the leaf blower cleaning. Only caution I have is to make sure you keep drifting snow away from it.

Probably will end up scrapping the 8" altogether.
Was thinking of going out and then up maybe 5 ft with the vent to save a 90.

If you mean going from the stove, horizontal out then 90 degree elbow and up 5 ft. that sounds good. Many installers encourage at least a 3 ft vertical so to promote draft, esp should you have a power failure and want to avoid your house filling with smoke. That 5 ft. up and an OAK should have you well installed. Do you have a cleanout T in this planned set up. Keep the whole install withing the suggested venting options in your manual and you should have a good burn and safe install. I am going to try to show an example of the inside vertical with a T.