Pelletvent Pro venting within joist cavity

[nscarnati]

Installing new stove in my basement, using Pelletvent Pro pipe which is listed as 1" clearance to combustibles. To meet all clearance requirements and have the stove in the corner, I need to run a 3' horizontal section through a 2x10 joist cavity (blue line). I reframed the joists to create the cavity shown.

Red line is the approximate grading outside, which is why I can't go straight out (wanted to avoid exterior vertical run) , and running it 3' horizontal will get me to a spot that's 3 feet off the ground (the clearance requirement for venting straight out horizontally).

I have at least 2-3" of clearance everywhere within this cavity, exceeding the 1" manufacturer requirement.

While getting ready to dryfit, I re-read everything I could find from manufacturer and elsewhere, and on a random stove retailer site, THEIR instructions for this pipe says "horizontal runs need to be 7" above combustibles and 9" below combustibles, or have heat shielding installed". Can't find anything from the manufacturer of the pipe or pellet stove saying the same, all just reference the "1" clearance to combustibles", not specifying if that's for both vertical and horizontal applications.

I'm the type to over engineer everything (I am an engineer), so I want to do it right and not burn the house down. Inspector wasn't knowledgeable, just said follow manufacturers clearances

 

[EatenByLimestone]

I’d go with manufacturer instructions, but if in doubt, call them! Or write to them and get it in writing!

 

[tbear853]

Stove venting will generally run cooler vertically as heat likes to move up. Stove venting running horizontal will stay hotter, as there is no "up". Grandpa's tobacco barns had open faced fire pits with the flue out the back, but the flue then went horizontal for a good ways before turning upwards. That horizontal pipe was way hotter that the upturned section.

 

[Ssyko]

you need to contact a CSIA certified installer for your questions. I just go buy the pipe mfg. and local Code. I will always error to safety for the customer. over engineering is not always a bad gig

 

[nscarnati]

Local code & inspector no help - sent an email with pictures out to Duravent's tech support, hopefully they have some additional guidance, since their documentation only states 1" to combustibles

Local stove stores I've contacted will only install stoves & pipes they sell, so that's a no go.

If Duravent says it's acceptable, was thinking of lining the cavity perimeter with kaowool board for extra precaution - any reason not to do that?

 

[rickwai]

With the double ell you will have a section that will not be accessible to clean without disassembly

 

[Jeremy6500]

I would go with the heat shield that is recommended for the horizontal runs. definitely better to have it than just trust the 1".

Are you leaving the joist space open? I would for a while to keep an eye on it and then make some kind of easy access to it

 

[nscarnati]

With the double ell you will have a section that will not be accessible to clean without disassembly

Have a cleanout adapter tee on the back of the stove - was planning to clean out pipe by running this snake (Rutland 3-Inch Pellet Stove/Dryer Vent Brush with 20-Feet Handle - Amazon.com) both up from the cleanout tee, and also coming in from the termination outside. attacking from both sides would make it only a single 90 elbow to navigate with this snake. will these not work on elbows? seems to be flexible enough

 

[Jeremy6500]

Have a cleanout adapter tee on the back of the stove - was planning to clean out pipe by running this snake (Rutland 3-Inch Pellet Stove/Dryer Vent Brush with 20-Feet Handle - Amazon.com) both up from the cleanout tee, and also coming in from the termination outside. attacking from both sides would make it only a single 90 elbow to navigate with this snake. will these not work on elbows? seems to be flexible enough

I would plan on using a leaf blower instead of a ling brush. It would clean it all out.

Also, leave access to the horizontal section somehow so you can pull it apart if needed.

 

[nscarnati]

I would go with the heat shield that is recommended for the horizontal runs. definitely better to have it than just trust the 1".

Are you leaving the joist space open? I would for a while to keep an eye on it and then make some kind of easy access to it

Unless I heat otherwise from Duravent, nothing saying a heat shield is required (yet). Just the stove retailer I found saying to have 9" clearance above, 7" below.

Will be leaving open for now, but rest of ceiling will be drywall, so planning to eventually close it up with a removable panel (for future access/service purposes). Panel material and type (solid/vented) will depend on observed temps and what I hear back from Duravent

 

[nscarnati]

I would plan on using a leaf blower instead of a ling brush. It would clean it all out.

Also, leave access to the horizontal section somehow so you can pull it apart if needed.

access will be taken care of (message above) - I normally attach a shop vac to opposite end i'm cleaning out pipe from to suck out the loose creosote. used this method in the past with my wood stoves. may give the leaf blower a try too for any loose material the shop vac doesn't get

 

[Jeremy6500]

Unless I heat otherwise from Duravent, nothing saying a heat shield is required (yet). Just the stove retailer I found saying to have 9" clearance above, 7" below.

Will be leaving open for now, but rest of ceiling will be drywall, so planning to eventually close it up with a removable panel (for future access/service purposes). Panel material and type (solid/vented) will depend on observed temps and what I hear back from Duravent

I would still do the heat shield, regardless. You know the old saying "Better to have it and not need it, then to need it and not have it"

 

[Jeremy6500]

access will be taken care of (message above) - I normally attach a shop vac to opposite end i'm cleaning out pipe from to suck out the loose creosote. used this method in the past with my wood stoves. may give the leaf blower a try too for any loose material the shop vac doesn't get

I have used both a shop vac and then a leaf blower.

I found the leaf blower to be far superior. Cleans things out better, plus easier/quicker then a shop vac/brush.

 

[nscarnati]

I would still do the heat shield, regardless. You know the old saying "Better to have it and not need it, then to need it and not have it"

agreed - if I get no additional direction from Duravent, what type of heat shield on insulation would be best, and if there any issues with these

ideas I'm kicking around -
1. kaowool/vermiculite boards lining perimeter of joist cavity to protect from heat
2. fabricate a metal heat shield in cavity or around pipe
3. wrap pipe with kaowool around pipe to trap heat from radiating into cavity - would this overheat the pipe too much?
4. cut hole in floor above and install grate to allow any heat buildup in the joist cavity to vent to bedroom above it. Concern with this if pipes were to leak CO. Have plenty of CO detectors throughout house, but always a concern

 

[Jeremy6500]

agreed - if I get no additional direction from Duravent, what type of heat shield on insulation would be best, and if there any issues with these

ideas I'm kicking around -
1. kaowool/vermiculite boards lining perimeter of joist cavity to protect from heat
2. fabricate a metal heat shield in cavity or around pipe
3. wrap pipe with kaowool around pipe to trap heat from radiating into cavity - would this overheat the pipe too much?
4. cut hole in floor above and install grate to allow any heat buildup in the joist cavity to vent to bedroom above it. Concern with this if pipes were to leak CO. Have plenty of CO detectors throughout house, but always a concern

I would probably do something like option #1.

#2 could be okay, only thing is that metal is gonna hold heat. Probably not enough to matter, but ya never know.

#3 I just don't like the idea of anything touching the pipe. Also ,make it hard to inspect the integrity of the pipe.

#4 Only way I would vent the heat would be to the outside. With it being close to the exhaust exit you may get exhaust fumes working there way back in the heat vent. I wouldn't vent the heat in to the house.....although a bunch of us have pipes running through a living space without any issue.....so may not matter