Pellet Stove Smoking from Chimney Pipe Seams

[RussellFamily]

We installed a St. Croix Prescott EXL two years ago and have had a really good run. We installed the Duravent 3" chimney liner kit ourselves, sealed the pipes with RTV, and were happy and warm. Two cold winters and 7 tons of pellets later, all was well...until last week.

We had a professional chimney sweep come out to clean the chimney liner that goes from the back of our pellet stove, up, through the wall, and up the 25' chimney. After he left, we started it up. Within minutes, smoke filled our first floor. We shut it off and called the chimney guy back. He came and checked the chimney with mirrors and said that it looked good. He started the stove up and saw smoke coming out from the elbow where it runs into the wall and recommended a new elbow.

Since then, we have replaced the elbow, the tee, the adjustable pipe, and the entire run of pipes on the interior of our house, sealing them with copious amounts of red rtv silicone. We also dismantled the stove and cleaned the exhaust fan, replaced the shaker plate, fire box, and fire bricks, cleaned every crack and crevice, and sadly still have a very smokey stove.

From the $150 chimney sweep to the replacement parts and the new venting, we are about $650 into this project. We have four tons of pellets sitting in the basement, a mounting oil bill, and five chilly kids. I can't help but go back to wondering why it worked fine until we had it cleaned, and why swapping out those parts (and beefing up the firebox) didn't solve the problem. It all looks fine to me...does anyone else have any ideas?

 

[Lousyweather]

ah.....good ole duravent........ICC, my friend! Good example as to why it really doesn't pay to scrimp on pipe.

 

[vinny11950]

i would guess it is the Duravent. the seals in the pipes probably got out of place when the chimney guy cleaned them. also they are known to leak a lot so copious amount of RTV sealant is required a lot of the time.

I think you got lucky on the first install and got everything right.

Do you have a stove adapter? if so make sure the space inbetween the two pipes is sealed with silicone. smoke tends to back out of there if there is a leak along the line.

Also, your 3 inch pipe might not be enough for the long run up 25 feet of chimney. you might need 4 inch pipe.

pictures would help.

 

[RussellFamily]

Would you have recommended something else? Duravent is what the local woodstove shop carried, so that's what we went with originally. When we had a problem, I called, hoping they would swap out the elbow under their "lifetime warranty." The night before, we had had our chimney guy, a firefighter, back in the house, and he put tape on the pies to stop the smoke from coming into the house. I explained that before sending pictures. After sending in several sheets of documentation and speaking with three people at Duravent, I got the following very arrogant response from their customer service rep. (He assumed from the tape on the pipes that we had used a combination of 3" and 4" pipes. We later spoke on the phone for over an hour, a complete waste of time, and he told me that he has never heard of a problem like this and I must have done something wrong, forgotten to use rtv, not allowed proper cure time, not used the right size pipes, etc etc. Even when I read him the model numbers off of the stickers on the pipes, he told me that I was lying because those were NOT the pipes in the picture I had sent...except that they were. ?! I'll post some pics in a minute. Thanks for weighing in.

Hello Colleen,

After reviewing the photos provided, it is obvious that the pipe was not installed correctly. As you may have discovered your pellet stove operates with a pressurized exhaust. Every pipe connection must have a pressure tight seal on every inner liner connection. By the amount of smoke you experienced it is obvious that the inners were not adequately sealed by your installer. Your connection from the 3” rear to the 4 inch Tee appears improvised as does the connection into the wall. The 3 inch pipe coming from the wall does not mate to the 4 inch vertical pipe section, at all. All the taped connections were incorrect installed and the appliance should not be operated until this is remedied. We would suggest using all 3 inch pipe from wall to rear of unit. You must seal every connection of the inner liner with a 500RTV high temp silicone sealant. Tape on the outer of the pipe is just holding back the leaks from the unsealed inner liner. If your inners are all the same diameter and sealed correctly this venting system will work properly. This is not a warranty issue, but is an example of a dangerous incorrect installation. I would demand a full refund if this was installed by a “professional”.



Nick Bruce| Technical Service Manager

M&G DuraVent, Inc.

800.835.4429 | fax 707.446.2742

877 Cotting Ct.| Vacaville CA 95696

 

[P38X2]

Did you check the area where the pellet vent meets the stove? Make sure that joint is at least taped and secured with a stainless screw. Duravent is notorious for leaking, especially articulating sections, ie; elbows. Did you make sure you degreased the pipe before you applied the RTV? A flashlight is VERY helpful in spotting leaks. Turn the lights off in the room and check it when you're starting the stove. If you have to, snuf out the flame a bit once it catches to ensure smoke is being produced for you to detect. Don't forget to check the seams that run the length of the pipe sections. Tape is also recommended on the joints and make sure you keep it as flat as possible. Sometimes, if you're at a tough angle, ripples can form which smoke will leak through.

My guess is the chimney guy knocked the piping around a bit and caused the leaks.

 

[RussellFamily]

This is the picture of the current install. If there was a loose connection somewhere higher (in the chimney where I can't see) would that cause smoking in the house? It's as if the smoke isn't going up and pooling in these pipes, but the blower is working just fine, so it should just go...

 

[RussellFamily]

Did you check the area where the pellet vent meets the stove? Make sure that joint is at least taped and secured with a stainless screw. Duravent is notorious for leaking, especially articulating sections, ie; elbows. Did you make sure you degreased the pipe before you applied the RTV? A flashlight is VERY helpful in spotting leaks. Turn the lights off in the room and check it when you're starting the stove. If you have to, snuf out the flame a bit once it catches to ensure smoke is being produced for you to detect. Don't forget to check the seams that run the length of the pipe sections. Tape is also recommended on the joints and make sure you keep it as flat as possible. Sometimes, if you're at a tough angle, ripples can form which smoke will leak through.

My guess is the chimney guy knocked the piping around a bit and caused the leaks.

The area where the pellet vent meets the stove isn't taped or screwed, so we can try that. It never was before either, though. I'll have to check with my husband about degreasing the pipe. I'm not sure if that's something he did first. We had a flashlight out, but it's like there is smoke coming from every seam. It starts with the elbow, which is why we replaced that first, but eventually, it's like the whole pipe has smoke coming right through it. So, I guess we try again with a smaller amount of smoke and see where it seeps through first?

Is there any way that it's something in the stove, or higher up, or should I concentrate on this five feet of sections?

 

[mikkeeh]

IS it possible that when the stove was cleaned...the pipe actually got plugged somewhere? So the exhaust fan in the stove is just building up pressure and forcing out the smoke. If all was well before the cleaning....Id verify that the smoke pathway is completely clear.

 

[PoopieBritches]

Sorry to hear of your dilemma.
It sounds as if there must be some sort of blockage, or uncoupled section of pipe?
From the pics,it looks like you do not have the OAK installed?
Shouldn't matter if it ran fine without it for 2 yrs though.
Did you check the intake thoroughly?
I have never used any sealant on the Duravent pipe, on either of my 2 PDVC's.
However,after cleaning I often will smell smoke on initial startup. But, the ash seems to seal it up after a short period of burning.
How did the stove appear to run after the cleaning?(flame)
Perhaps you can open a window when starting, just to see how the stove is actually running?
That is a ridiculous response from Duravent too.

 

[webbie]

Does sound like the sweeping did away with the seals.......no reason it would work for years and then, all of a sudden, leak....

Pellet venting is positive pressure - that is, the pipe has pressure in it as opposed to the usual partial vacuum (draft). But natural draft can play a part also.

I'm not sure what the spec is, but it makes sense that this pipe cannot take too much positive pressure - that is, if it's even slightly clogged or the combustion fan is too strong, it could leak out. I've seen smoke leak right out through continuous welds on steel stoves.....so although you can seal pipe, there is always a pressure at which those seals will fail.

 

[vinny11950]

you must have screws connecting the vent pipe to the stove. otherwise they may come apart under the perfect circumstance and burn the place down. also, the stove exhaust collar needs a bead of RTV silicone so when the stove pipe adapter goes over it it seals tight. then 3 screws to keep it in place.

this is the link to the install manual:

(broken link removed to http://www.eventempinc.com/stcroix/downloads/analog/St_Croix_Installation_Manual_11-12-03.pdf)

page 7, top of page, says you need 4 inch diameter pipe.

this is not your immediate issue, but it does put a lot of stress on the exhaust blower motor and creates added pressure that is pushing out the gasses through the pipe seams.

you need to be very careful now, triple checking everything in the stove and the stove pipe against the installation manual.

see this video

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[Lousyweather]

cant say as Im thrilled with the Duravent response either......it would seem SOMETHING was done upon cleaning.....who knows? Were the elbows stressed, the RTV bonds broken....immaterial really, as they now leak, for whatever reason. Its not the stove, its the pipe....enough RTV and foil tape might solve the problem (after looking for blockage). My suggestion is to totally remove the offending pipe and replace with a quality brand....and the one to use is ICC. I know its not what you'd like to hear, but that's my solution.

 

[webbie]

Hate to spend more of your money, but if you want the true and honest scoop, call up Scott (a member here) and see if you can have him or his pros check it out. He's probably in the top-top-top of the class of pellet knowledge.....

Maybe you get better placement on the schedule by PMing him here!

https://www.hearth.com/talk/members/smwilliamson.13019/

 

[Harvey Schneider]

I would check to see if the top of the vent is blocked.

 

[ollie g]

5 kids! wow! We own a 1885 log structure with heating units, such as four pellet stoves,2 gas furnaces,5 overhead infrared lamps and 1 small Dovre gas stove. The Dovre is used for our living space of 700 feet. The pellet stoves are used primarily for studio's. All the pellet stoves were purchased used, off of craigs list. Because of different applications I have had to buy pipe. Dura Vent seems to be good pipe. Sometimes its hard to lock together but if you clean the ends and put a light dab of something slick like vaseline around the connection, along with the help of a partner or some pipe grabbers you can lock those babies tight enough that they won't leak without using that red calk crap. Ya, I know, oh my God there is a guy out there that doesn't use the red calk crap and he's is going kill us all, the man is a danger to the world and he's going to burn for sure. Well, as much as I wish sometimes this money pit would burn down I have yet to see any smoke coming out of anywhere it shouldn't be. The pipes work great and if I what to clean them I can. Once, red crap calked, they are very very hard to get apart. I know.

This is what I suggest.
plan A................................... Delegate
If you know the name of your stove, call that company. I have and it works. Next, get out the manual and give it to your oldest kid and tell (him or her)
that they are the pellet stove expert. Learn everything about that stove and trust no one to mess with it except the pellet stove expert. Clean it often and send your pellet stove representative a holiday greeting and a thank you. Spend what you have to, to get it right. The stove will pay you back pronto.

plan B...................................Call out the troops (mass media)
Rally the kids up in front of the stove with coats,sniffles, blankets and make a youtube video of your suffering, don't be shy, cry, have them cry. Say it all loud and clear about everything, about the stove, the kids, the cold, have the kids in the back ground start fighting, yell at them, scream and look into the lens of your camera, point your finger and say these words "all because of you Mr.chimney sweep bastard" It was working fine until you touched it. I hate every one of you son of a bitches at Dura Vent you have wrecked my life. you are going to pay. I want change and I want it now. Send it to them and see what happens.
the squeaky wheel thing never fails.........you'll get it


ollie