Recommended flex pipe brand? Draft Issue!

[Cold1313]

Hi all,

I am looking for some recommendations on brands of stainless flex pipe for my second pellet stove in my basement. When I installed my new Harmon insert last year, I purchased the flex pipe from the dealer and ran it down my 12"x12" clay flue with the appropriate cap and vent on the top of the chimney. I feel like I was over charged on the flex pipe, so I'm looking to see what I can order online.

For the stove in the basement I would run double wall hard pipe out of the stove, up to the hole in the 12"x12" clay flue (previously used for a gas water heater I believe). I live in a ranch home and the hole in the flue is probably 6' off the floor in the basement. Not a huge run but not short. I am hoping this will help create a great natural draft?

Thanks for the recommendations!



I'm ordering because of this issue - if you care to read on and comment, I appreciate it!

Previous setup:
TSC stove, hard pipe vent to the hole in the flue and let the gas run up the flue on it's own. Worked fine, no issues. Lots of CO2 monitors, no issues.

A used Harmon stove was given to me by a close friend and I swapped the stoves, since the Harmon had more controls. Set in the same location, same pipe setup, no issues. Worked nice....only used it a few times last winter.

Then the issue occurred. Late winter, approaching spring, hadn't run the stove in well over a month. Turned it on as normal and smoke starts leaking out of the twist lock joints on every pipe. I immediately shut it down. I never had a true fire in the stove because as soon as I saw smoke from igniting the pellets, I turned it off.

NEVER had this issue - nothing changed from when I turned it off from when it was used before. Odd that I had smoke at the joints. Put a lighter by a seam at the stove pipe and clay flue and it pulls the flame in. Seems to be drafting fine.

After verifying no clogs top and bottom, different pipe configurations (shorter run) - no change. Spring came and I left it alone. (This stove was just used on very cold days to warm the floors in the house...not a lot of use.)

Spoke with a few different people and the only thought is that the wind or pressure from outside was pushing the smoke in the house - with the large clay flue working against me.....all of a sudden apparently? Since it worked fine before.... (even though it pulled the lighted flame into the flue) Seemed odd, but who knows.

The suggestion was to drop a flex pipe from the top of the chimney down to the hole in the flue in the basement. That way I am not venting to the 12"x12" clay flue...less air to heat, hopefully a better draft. The cap for the flex pipe would gain me 6-12" of additional height up top, can't hurt. Yes, my previous way of venting directly into the flue wasn't the greatest idea, so I feel better doing this flex pipe - but would this solve my stove issues?

Less air to draft with the flex pipe vs the big clay flue. I never got around to putting my TSC stove back in place to see if I had a draft issue. So it's possible that my "new to me" Harmon stove, randomly had an exhaust blower issue (it was working). Just an odd situation that it was fine one month, then the next time I light it up, I have these odd issues.

So does the logic of running double wall hard pipe, to the hole in the flue, and connect to flex pipe to have a great draft make sense?

Can't seem to figure out what else the issue could be!

 

[DAKSY]

Hi all,

I am looking for some recommendations on brands of stainless flex pipe for my second pellet stove in my basement. When I installed my new Harmon insert last year, I purchased the flex pipe from the dealer and ran it down my 12"x12" clay flue with the appropriate cap and vent on the top of the chimney. I feel like I was over charged on the flex pipe, so I'm looking to see what I can order online.

For the stove in the basement I would run double wall hard pipe out of the stove, up to the hole in the 12"x12" clay flue (previously used for a gas water heater I believe). I live in a ranch home and the hole in the flue is probably 6' off the floor in the basement. Not a huge run but not short. I am hoping this will help create a great natural draft?

Thanks for the recommendations!



I'm ordering because of this issue - if you care to read on and comment, I appreciate it!

Previous setup:
TSC stove, hard pipe vent to the hole in the flue and let the gas run up the flue on it's own. Worked fine, no issues. Lots of CO2 monitors, no issues.

A used Harmon stove was given to me by a close friend and I swapped the stoves, since the Harmon had more controls. Set in the same location, same pipe setup, no issues. Worked nice....only used it a few times last winter.

Then the issue occurred. Late winter, approaching spring, hadn't run the stove in well over a month. Turned it on as normal and smoke starts leaking out of the twist lock joints on every pipe. I immediately shut it down. I never had a true fire in the stove because as soon as I saw smoke from igniting the pellets, I turned it off.

NEVER had this issue - nothing changed from when I turned it off from when it was used before. Odd that I had smoke at the joints. Put a lighter by a seam at the stove pipe and clay flue and it pulls the flame in. Seems to be drafting fine.

After verifying no clogs top and bottom, different pipe configurations (shorter run) - no change. Spring came and I left it alone. (This stove was just used on very cold days to warm the floors in the house...not a lot of use.)

Spoke with a few different people and the only thought is that the wind or pressure from outside was pushing the smoke in the house - with the large clay flue working against me.....all of a sudden apparently? Since it worked fine before.... (even though it pulled the lighted flame into the flue) Seemed odd, but who knows.

The suggestion was to drop a flex pipe from the top of the chimney down to the hole in the flue in the basement. That way I am not venting to the 12"x12" clay flue...less air to heat, hopefully a better draft. The cap for the flex pipe would gain me 6-12" of additional height up top, can't hurt. Yes, my previous way of venting directly into the flue wasn't the greatest idea, so I feel better doing this flex pipe - but would this solve my stove issues?

Less air to draft with the flex pipe vs the big clay flue. I never got around to putting my TSC stove back in place to see if I had a draft issue. So it's possible that my "new to me" Harmon stove, randomly had an exhaust blower issue (it was working). Just an odd situation that it was fine one month, then the next time I light it up, I have these odd issues.

So does the logic of running double wall hard pipe, to the hole in the flue, and connect to flex pipe to have a great draft make sense?

Can't seem to figure out what else the issue could be!

What brand of pellet vent are you using?
Have you tried RTV silicone or aluminum tape to seal the pipe joints?

 

[Cold1313]

What brand of pellet vent are you using?
Have you tried RTV silicone or aluminum tape to seal the pipe joints?

I'd have to go look at the pipe but it shouldn't leak, it is twist lock and I even taped it and still had smoke issues. Out of the blue...very odd....so before I drop coin on flex pipe down to it, I'm curious if it will help.

The main question is what brand flex pipe and where to buy?

 

[DAKSY]

Hmmm...The excess smoke may be caused by the CFM rate between the TSC stove & the Harman.
If the Flue in the chimney was super cold & the Combustion blower tried to push the exhaust thru the
vent faster than the bigger chimney could evacuate it, it would exit the seems. I use & recommend Excel
Pellet Vent for connector on my Harmans. RTV silicone gaskets built into each piece prevent blowback.
What is your total rise off the stove? You may need to go to 4" if the run is greater than 15'...
Here's Home Depot's 4"; https://www.homedepot.com/s/4%22%20pellet%20chimney%20liner?NCNI-5

 

[Cold1313]

Hmmm...The excess smoke may be caused by the CFM rate between the TSC stove & the Harman.
If the Flue in the chimney was super cold & the Combustion blower tried to push the exhaust thru the
vent faster than the bigger chimney could evacuate it, it would exit the seems. I use & recommend Excel
Pellet Vent for connector on my Harmans. RTV silicone gaskets built into each piece prevent blowback.
What is your total rise off the stove? You may need to go to 4" if the run is greater than 15'...
Here's Home Depot's 4"; https://www.homedepot.com/s/4%22%20pellet%20chimney%20liner?NCNI-5

Your thinking is inline with mine - maybe the new to me Harmon had trouble pushing exhaust into the large flue. However the flue wasn't super cold (compared to when I ran it in mid-winter) and it worked without a single leak. I was going into Spring for a burn to empty the hopper and that's when she started smoking at the pipe joints. Very, very odd. I'm hoping if I drop down a 4" flex pipe down the chimney, it will draft like crazy. Does that sound correct?


Here are my exhaust setups - please let me know if you see an issue. I've had three setups that worked (until spring time when both setups smoked)
1) ~1 foot hard pipe out of the stove to a clean out tee. This then angled 45* towards the hole in the flue. 90* turn into the flue and open exhaust to the flue. (This worked without issues with both stoves in winter. Then started smoking on the new stove in spring time. I then tried setup 2 and 3 below - which smoked)

2) ~4 foot hard pipe out of the stove to a clean out tee. 90* up ~6 feet. 45-90* bend into the open flue. Smoked with old stove.

3) ~1 foot hard pipe out of the stove to a clean out tee. 90* up ~6 feet. 45-90* bend into the open flue. Smoked with old stove.

So going forward, I would use a hard pipe setup to the flue, then connect to the flex pipe up the flue. Thoughts?

 

[Cold1313]

I'm going to get some 4" flex on order for the flue. Then in the basement where I exit the flue to the stove - and switch to hard pipe, double wall....should I keep it at 4"? Or 3" hard pipe to 4" flex?

Either way, this Harmon was made to have a 3" connected to the back.