Work at a shop that sells stoves and had to do a reinstall of pellet pipe because the old was leaking. Used all new pipe (Pellet Vent Pro) came off the tail pipe to a clean out up to a 90 and out. Siliconed the tail pipe as well as around the pipe going out but still the pipe is smoking. You can see it and I am at a loss as to why other than the thought of negative pressure in the building and how to test for it.
Smoke in my eyes
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SmokeyTheBear
Minister of Fire
If the pipe is smoking it isn't because of negative pressure in the house. You missed something in your installation process now by the book each piece attached to the stove's exhaust was and exactly how did you attach it? How long were any screws you used which if any screw hole(s) did you pilot using a drill? How did you prep the clean out tee? Did you inspect the vent for out of place or damaged internal seals?
boosted3g
Feeling the Heat
I just used some pellet vent pro on my new install and some of them fit extremely tight. I had to really use some force to turn some of the connections on the entire way. Maybe one might be a little tight and not fully connected. Make sure the o-rings in there are lubed up good and slide together nice.
Harman XXV came off the tail pipe with six inch put red rtv silicone on pipe and a half inch stainless self drilling screw to mount a cleanout T then a six inch along with a twelve inch adjustable with red rtv then a 90 out the thimble, a twelve, a six and finally the cap. Had leakage before in this set up they had silicone on every joint thats why the new set up was to be done. On each piece I went ocd and slid them together twice to make sure they were all the way in to the ring inside then I locked them twice just to make sure I felt the end of the grove on the male end and that they were locked. When the stove started I thought I was all set but there was some odor then I saw smoke coming off the pipes including the 90. I also silicone around the pipe where it went through the thimble. There is no OAK on this system.
not a fan of simpson- 90's and tees are notorious leakers......ICC rocks! How about using a stove adapter on that nipple rather than a 6" piece? The adapter has an elongated internal section that goes inside the nipple, allowing for much improved sealing.
As an aside, we moved to ICC because the simpson pipe leaked so much....yes, the ICC costs more money, but that difference is eaten up in the amount of time spent looking for leaks and having to go back to a house where someone smells smoke.....often the bottom cap of the tee, FWIW.
As an aside, we moved to ICC because the simpson pipe leaked so much....yes, the ICC costs more money, but that difference is eaten up in the amount of time spent looking for leaks and having to go back to a house where someone smells smoke.....often the bottom cap of the tee, FWIW.
SmokeyTheBear
Minister of Fire
Did you put a stove adapter on the stoves exhaust before going with the normal vent sections?
Stove adapters are notorious for leaking usually because they were not properly fastened to the stove's exhaust pipe, silicone sealant should be applied to the inside of the adapter and slid over the stove's exhaust pipe making certain it is completely on and the adapter fastened mechanically with screws that you drilled a pilot hole for and placed a dab of sealant in before the screw, this along with a bead around where the adapter's pipe sleeve goes over the stoves exhaust pipe on the stove side.
Clean outs need their clean out caps sealed using high temperature metal flue tape and their saddle joints sealed with silicone or tape (the saddle joints can part company a bit if the the venting gets struck or flexed).
The joints on elbows especially those that form the bends can also leak and likely should be taped.
Then there is the possibility that the smoke is coming out where the exhaust fan housing meets the stove.
I'd also see about using a shorter screws so that he inner pipe doesn't get punctured.
Stove adapters are notorious for leaking usually because they were not properly fastened to the stove's exhaust pipe, silicone sealant should be applied to the inside of the adapter and slid over the stove's exhaust pipe making certain it is completely on and the adapter fastened mechanically with screws that you drilled a pilot hole for and placed a dab of sealant in before the screw, this along with a bead around where the adapter's pipe sleeve goes over the stoves exhaust pipe on the stove side.
Clean outs need their clean out caps sealed using high temperature metal flue tape and their saddle joints sealed with silicone or tape (the saddle joints can part company a bit if the the venting gets struck or flexed).
The joints on elbows especially those that form the bends can also leak and likely should be taped.
Then there is the possibility that the smoke is coming out where the exhaust fan housing meets the stove.
I'd also see about using a shorter screws so that he inner pipe doesn't get punctured.
Did not use an adapter just a straight six inch pipe with rtv silicone and one screw to mount it to the tail pipe, no other screws were used. Talked to a duravent rep and was told to use silicone between the two wall of the last section of pipe outside to prevent smoke from being drawn back in. He thinks there may definitely may be a negative pressure problem so I am now going to add an OAK to the system. Some people may prefer ICC but I can't believe that the Duravent is this bad and still being used commercially and I have seen enough installations using the Duravent with no leaks. I have to make this work I think it will go a long way towards my understanding of pipe installation and pressure dynamics. I'll let you know what happens.
Thanks for all the advice and help.
Thanks for all the advice and help.
SmokeyTheBear
Minister of Fire
It isn't negative pressure the venting is all under positive pressure after the combustion blower.
The smoke is coming out the wrong place for it to be negative pressure if it is coming out the vent pipes, air intake yes, but your vacuum switch would likely have killed the stove if it was that bad.
The smoke is coming out the wrong place for it to be negative pressure if it is coming out the vent pipes, air intake yes, but your vacuum switch would likely have killed the stove if it was that bad.
jtakeman
Minister of Fire
I'm with STB. Positive pressure.
PVP isn't leak free without adding silicon to the interior joints and also adding silicone or tape to all the seams inside the house...... Not using an adapter could be an issue. It allows any smoke that gets into the void area between the 2 pipe walls to exit. The adapter has a seal stuffed in it! If its a must not use an adapter. You must fill the void full of silicone(I mean pack it in as far as you can) to seal that area up solid. If you can see in between the pipes its gonna leak!
PVP isn't leak free without adding silicon to the interior joints and also adding silicone or tape to all the seams inside the house...... Not using an adapter could be an issue. It allows any smoke that gets into the void area between the 2 pipe walls to exit. The adapter has a seal stuffed in it! If its a must not use an adapter. You must fill the void full of silicone(I mean pack it in as far as you can) to seal that area up solid. If you can see in between the pipes its gonna leak!
heat seeker
Minister of Fire
I think maybe he was referring to negative pressure in the house, drawing smoke back in…??? Hence the OAK…although there may be other causes for the negative pressure.
SmokeyTheBear
Minister of Fire
He thinks that negative pressure in the house is the reason his pipes are smoking. Not very likely considering where the pipes are that are smoking. Wrong place and he really has to vent that thing correctly and attaching the venting via a 6" piece of venting isn't correct. He has plenty of ways for the smoke to get between the inner and outer wall of the vent and then to be forced out into the room by the combustion fan as it is all on the positive pressure side of the stove. Adding the OAK will not help unless the smoke was exiting the air intake. If the smoke was exiting the air intake while the fire was lit it would be a rare occurrence as long as the combustion fan was turning in the correct direction. Also the vacuum switch should have killed the feed.
If the smoke is coming in from the outside then the vent is in the wrong place (too close to an opening in the wall such as a window) or he forgot to seal the venting's annulus on the outside of the thimble. I can't think of a single thing an OAK would do to help that situation.
heat seeker
Minister of Fire
Now I get it! No, an OAK won't help in that situation, other than slightly reducing the negative pressure. I do wonder what's causing that much negative pressure, and how the smoke is getting in. But that's just what we're trying to figure out…Sounds like the installation leaves something to be desired.
I'll go back to lurking now.
I'll go back to lurking now.
With regards to the connection to the stove the six inch piece has rtv silicone between the two walls I put it there before I attached to the tail pipe. That was the way I was shown to do my connection. There are no openings outside where the pipe terminates. Don't know what an "annulus" is but if you are speaking about the wall thimble I put silicone around the pipe going through both inside and out.
SmokeyTheBear
Minister of Fire
The annulus is that open ring around where the vent passes through the thimble.
Have you darkened the room the stove is in and using a flashlight during start up only looked for smoke? Or used a smoke source inside the firebox this will find all exit points for smoke the stove and venting has this includes air washes, through the non spinning combustion blower shaft hole, any scrapper rod penetrations, the air intake, and the hopper if not sealed or well filled.
It is also possible that the combustion blower housing seal is leaking.
Yep.. What Smokey said. Turn off the lights, get a bright flashlight, and a tube of High temp silicone.
Be ready on start up to look for smoke. Or simulate the stove running (combustion blower), and place a smoke bomb inside the firebox.
Either way, its gonna take some RTV.
Be ready on start up to look for smoke. Or simulate the stove running (combustion blower), and place a smoke bomb inside the firebox.
Either way, its gonna take some RTV.
Hello
I would go get a stove adapter if I were you.
I just fixed a stove with a hopper fire and the owner wondered why there was so much soot in the room. I looked at the back and NO stove adapter!
After replacing the auger, auger collar, auger motor, control panel, and upgraded the exhaust blower from 85 to 105 cfm it works much better with a STOVE adapter!
I would go get a stove adapter if I were you.
I just fixed a stove with a hopper fire and the owner wondered why there was so much soot in the room. I looked at the back and NO stove adapter!
After replacing the auger, auger collar, auger motor, control panel, and upgraded the exhaust blower from 85 to 105 cfm it works much better with a STOVE adapter!
The room is dark enough behind the stove to shine a light across things to see smoke near as I can tell the smoke is coming from the pipe especially the last 90 before it goes out nothing from around the stove (Harman XXV) but I will check the comb blower for leaks. I will also replace the first pipe attached to the tail pipe with an appliance adapter. Perhaps I should just fill all the space between the walls of the pipe inside with rtv although I don't think this answers the question of where is the smoke coming from or why. I really want to resist putting silicone or tape on the joints of the pipe it looks unprofessional and says I haven't corrected the problem. I'm curious Don222 how you determined what motor to use (upgraded the exhaust blower from 85 to 105 cfm). I also don't know how to use a smoke bomb in the stove to determine a leak. So much to learn!
The smoke is coming from the vent. Pellet Vent Pro is Notorious for leaks. But not having a stove adapter, your shooting yourself in the foot. The stove is negative pressure (no smoke) and the vent is positive pressure (smoke/leaks). Its likely coming from the 90°'s, Clean out T's and the stove adapter area.
All the amswers to your questions are above. Use Clear High temp RTV and apply sparingly. Wont hardly be noticed.
As for Don's post, there is no other blower for the stove your working on, doesn't pertain to thread.
(Smoke bomb - Have stove in test mode w/ combustion blower running, light smoke bomb / like the ones you lit as a kid / close door, inspect for leaks)
SmokeyTheBear
Minister of Fire
Well let's see the smoke is in the venting because it is going to be banished to the outside world.
The smoke exists because the pellets smolder before they ignite.
This happens because you are using a resistance heater to pyrolyze the wood pellet until it exceeds its ignition temperature.
It gets out of the venting in all of the wrong places because it isn't installed properly or is damaged during the install (to long in the screw department can do that as can not supporting any vertical runs below and above elbows or tees), or is defective.
I think that about covers the matter.
The smoke exists because the pellets smolder before they ignite.
This happens because you are using a resistance heater to pyrolyze the wood pellet until it exceeds its ignition temperature.
It gets out of the venting in all of the wrong places because it isn't installed properly or is damaged during the install (to long in the screw department can do that as can not supporting any vertical runs below and above elbows or tees), or is defective.
I think that about covers the matter.
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