Enviro Mini exhausting into house

zizzlah · Nov 27, 2011

Hi Everybody. I hope you can help me. I've had my Enviro mini for 4 or 5 years now, and it has been an intermittent performer for me. Initially, the problem was a strong smoke smell on start-up that persisted as the stove ran. The dealer's repair person was useless, although he was able to use a magnahelic to set the combustion air, and the dealer got increasingly unresponsive. Within months, that dealer was out of business. I read Rod P's site and changed the venting system: I added a 90 and an 8' vertical run to the existing 3' vertical run with a 90 to an 12" horizontal (I'm on a houseboat, and have to go up before I can go out). I could still smell smoke, but it was a little better. I run it mostly on the low setting.

It's never burned consistently - one day the flame is whipped by the air, one day it's lazy. Some times the smoke smell has me plugging in the space heater, and other times I just open the windows and live with it. The glass has always clouded up and the flue pipe is coated with black soot - all 12 feet of it (fine and powdery). Until this weekend, I thought I was cleaning it adequately because I never got an owner's manual and the repair guy assured me I just had to empty the ash holder, which I did faithfully. (I was a little nervous about this as my old Whitfield required much more than this, but I was willing to be lulled). On Friday, I turned on the stove then went upstairs to sip some tea. I could see - and smell - white smoke billowing up from somewhere; turned out it was my flue.

Smoke was pouring out of the stove - no flame - and leaking out of the joints of the flue. The stove was silent - no fans were running. I (carefully) used a fire extinguisher to put it out, then cleaned up the mess. I went online looking for answers and found the latest user manual with terse cleaning instructions (no pictures). I cleaned out the ash from the crevices behind the ash pan (after removing the access panels) and behind the walls in the burn chamber, which I also removed. I pulled the flue pipe out of the back of the stove and vacuumed the T in the flue pipe and the opening to the exhaust fan. I haven't cleaned the rest of the flue (the 90 outside).

Now the flame is tiny and bright, and whipped by air, and it puts out heat. Problem is, the smoke smell is worse than ever. It's most pronounced in the back of the stove generally and at it's absolute worst during start-up. I can't use the stove without feeling ill and having my eyes burn, so I've unplugged it. Oh - before I unplugged it, I hooked up the flexible hose from my shopvac to the fresh air intake to see if that helped, and it made no difference. My dealer is gone and Enviro was of no help in the beginning, so I have my doubts about them being of use. I'm sure I'm missing something key, but I can't figure out what it is. Can you help? I'd like to love my Mini as much as the rest of you seem to. Thank you.

SmokeyTheBear · Nov 28, 2011

You need to do a re installation of the venting from the stove on out, using the proper fasteners and the correct sealant.

When you do this you need to take the time to completely clean the stove and any of the venting you plan on reusing.

That stove needs to be treated the same as any pellet stove, it has hidey holes for ash (ash traps, just like your Whitfield). These need to be located and cleaned.

I don't know how much you have put through the stove but if it is more than a ton since the last time the combustion blower was pulled and cleaned you need to get the correct gasket, pull,clean the impeller, the cavity it sits in and the air path both towards the heat exchanger and towards the vent pipe.

jdempsey · Nov 28, 2011

5 Years and never properly cleaned.Sounds like this stove needs to be torn down and a complete cleaning from the flue to the combustion blower and everything in between.

Do not run this stove till you get it fixed. You could become a tragic victim from carbon monoxide poisoning.

zizzlah · Nov 28, 2011

Here's an update: removed all 3 caps and dumped the accumulated ash in each (after first tapping the verticals). The two on the outside T were full, the one on the inside was about 1/3 full. When I removed the inside T, I realized that the adapter piece of flue pipe is caulked to the stove, but just sits inside the T - it's not twisted and locked in. Instead, it's got a piece of metal tape on it. I guess the installer caulked the piece to the stove before they twisted it into the T.

When I started up the stove this time, the smoke smell persists. It's quite strong, and still renders the stove unusable. I can't detect any difference. Could it be this taped joint? I can't see any smoke leaking out, and even when the stove was belching smoke and the properly fitted joints were leaking slightly, this taped joint was fine. Thanking you all in advance.

SmokeyTheBear · Nov 28, 2011

Liz W. said:
Here's an update: removed all 3 caps and dumped the accumulated ash in each (after first tapping the verticals). The two on the outside T were full, the one on the inside was about 1/3 full. When I removed the inside T, I realized that the adapter piece of flue pipe is caulked to the stove, but just sits inside the T - it's not twisted and locked in. Instead, it's got a piece of metal tape on it. I guess the installer caulked the piece to the stove before they twisted it into the T.

When I started up the stove this time, the smoke smell persists. It's quite strong, and still renders the stove unusable. I can't detect any difference. Could it be this taped joint? I can't see any smoke leaking out, and even when the stove was belching smoke and the properly fitted joints were leaking slightly, this taped joint was fine. Thanking you all in advance.

Take that venting off and reinstall it correctly, every joint must be mechanically bonded and all joints gas tight. Nothing in the vent should just set inside another part of the venting and be held together by a piece of tape.

You have been living with a very dangerous setup.

zizzlah · Nov 28, 2011

Not 5 years without *any* cleaning! When I had the entire length of vent replaced the year before last, I vacuumed everything in the stove I could get the hose into. So, 2 years for the flue. I had the stove apart at the end of the winter last year and the fans, etc., looked fine. I kept thinking "where is all the ash?" and "what a clean stove." I had no idea about the hidey holes in the ash cavity. It's only the those that have gone 4 or 5 years without cleaning. Had: they are clean now.

But, I take your point: there is no telling where that hidey hole ash traveled. So, in the stove, I need to take out all the fans them and make sure the entire pathway is clean, right? Even though it looks clean inside the stove, the ash may be in the actual pathways. Without any diagrams, pictures or videos (all lacking for the Mini), I doubt I'll recognize an impeller, but I can follow a pathway. So I'll do that and report back. The flue is another matter.

What's puzzling about your flue advice is the contractor who installed the new vent pipe followed the duravent instructions exactly, except for that one joint, which he assured me would be fine with the tape. I remember talking to him about how counter-intuitive and confusing the instructions were. Are you saying that if the joints were properly caulked they would not have leaked when the stove was belching smoke? (My reference is a wood stove, where the flue pipe was fitted more casually and would leak if the conditions were right.) If they should hold no matter what, then I'm alarmed that they leaked. Although I've installed several stoves with the old duravent pipe, I'm not at all confident I can do better with the new stuff. It has you putting caulk inside the pipe in a way that makes it impossible to verify that it's sealed it. I will take it all apart and brush out the flue as you suggest. What do you think about running a bead of high-temp caulk around the outside when I've taken my best shot at reassembling it, just for insurance?

Thank you for your advice and your patience with me.

SmokeyTheBear · Nov 28, 2011

Liz W. said:
Not 5 years without *any* cleaning! When I had the entire length of vent replaced the year before last, I vacuumed everything in the stove I could get the hose into. So, 2 years for the flue. I had the stove apart at the end of the winter last year and the fans, etc., looked fine. I kept thinking "where is all the ash?" and "what a clean stove." I had no idea about the hidey holes in the ash cavity. It's only the those that have gone 4 or 5 years without cleaning. Had: they are clean now.

But, I take your point: there is no telling where that hidey hole ash traveled. So, in the stove, I need to take out all the fans them and make sure the entire pathway is clean, right? Even though it looks clean inside the stove, the ash may be in the actual pathways. Without any diagrams, pictures or videos (all lacking for the Mini), I doubt I'll recognize an impeller, but I can follow a pathway. So I'll do that and report back. The flue is another matter.

What's puzzling about your flue advice is the contractor who installed the new vent pipe followed the duravent instructions exactly, except for that one joint, which he assured me would be fine with the tape. I remember talking to him about how counter-intuitive and confusing the instructions were. Are you saying that if the joints were properly caulked they would not have leaked when the stove was belching smoke? (My reference is a wood stove, where the flue pipe was fitted more casually and would leak if the conditions were right.) If they should hold no matter what, then I'm alarmed that they leaked. Although I've installed several stoves with the old duravent pipe, I'm not at all confident I can do better with the new stuff. It has you putting caulk inside the pipe in a way that makes it impossible to verify that it's sealed it. I will take it all apart and brush out the flue as you suggest. What do you think about running a bead of high-temp caulk around the outside when I've taken my best shot at reassembling it, just for insurance?

Thank you for your advice and your patience with me.

If the joints are properly sealed they can not leak smoke, now I do not know your contractor, but if he did not mechanically fasten even one joint in the venting he wasn't following the vent makers instructions. Now about that venting you have, it is prone to leaking at joints and in seams. Why, I don't know, but a lot of folks on here have had problems with it. Perhaps a lot of folks take short cuts. If so venting is the very last place to do that.

zizzlah · Nov 28, 2011

"...prone to leaking at the joints and seams." Well, that's not good news, is it? BTW - this new version of Duravent flue has no seams. Perhaps, as the were unsuccessful with making seams that didn't leak, they gave it up? But, it certainly leaks at the joints, even when the ones that were installed correctly. I'll fix the one that wasn't. My question remains: Can I correct the deficiency, no matter who is responsible for it, by running bead of caulk around the outside of the joint?

hoverfly · Nov 28, 2011

If you can, We could use some pictures of the set up.

I am also wondering if you replaced any of the gaskets on the stove it self? How about the door? Do you keep the bin closed? Does it have it's gasket in place?

Now you had the air adjusted with the gauge did he use the right gauge and number? Is the air adjustment slider even open?

Are the air intakes free of obstruction?

Also you pointed out that you have 12 feet of vent pipe? If you are using 3" diameter pipe it my be to much you may need to go 4" vent.

On my Mini I am using two vertical 5 ft lenght pipe one 45 degree and one 90 degree. That gives me a EVL 13, for 3 diameter vent it's a Max of 15.

How to Vent your Pellet Stove Take a look at this link to figure out if you are ok.

DexterDay · Nov 28, 2011

Yes. Definitely put high temp RTV silicone on all joints if they are leaking. I have had decent luck with the Simpson Dura-vent Pellet vent Pro. But I just installed another stove this week and had to seal all of the joints (only 2 needed it/but did them all).

Simpson does have a bad reputation for leaking at the seams. The factory seals are not that great. Get some High Temp RTV (silicone/caulk) rated for at least 500* and seal them up...

Also pics of the set-up would be nice. A pellet stove on a house boat sounds sweet.

imacman · Nov 28, 2011

Liz W. said:
I can't see any smoke leaking out, and even when the stove was belching smoke and the properly fitted joints were leaking slightly, this taped joint was fine.....

Just because you didn't see it, doesn't mean it's not there.

Just to make sure you got ALL the leaks sealed, do a check (at night): Start stove, and as soon as the pellets start to smolder, quickly turn out all the lights in the room, and shine a flashlight all over your pipes....the flashlight beam should illuminate the smoke location, if any.

Don't take chances with leaks and CO.

SmokeyTheBear · Nov 28, 2011

I'm glad you folks stepped in as I was in the middle of a very large (5 hour) software upgrade and it seems that at least one of the 3809 new packages is giving me trouble so I have been off air for a bit.

Various points that are known to cause issues in a lot of venting is the saddle joint on any tees and the clean out cap.

But the single biggest problem is the stove adapter.

It does help us if we can see what is there.

imacman · Nov 28, 2011

SmokeyTheBear said:
.....I was in the middle of a very large (5 hour) software upgrade and it seems that at least one of the 3809 new packages is giving me trouble so I have been off air for a bit.....

What was this? A software upgrade for a PC? 5 hrs??? :gulp:

ChandlerR · Nov 28, 2011

Liz, welcome! You will get the best advice here, I'm sure of it! I just wanted to chime in here and say that the difference in the exhaust of your pellet stove, and say, a wood stove, is that there is air pressure in your venting. That is why there has to be a mechanical connection between each section of pipe. There is no natural draft to speak of. Now, at the outlet of the stove itself, at least on mine, there is an adaptor that is secured to the stove with a heavy duty hose clamp and the other end has the twist lock for the vent pipe. I have no tape at all anywhere and no smell.

Hang in there, be patient, and maybe get us some pictures so we can get a good complete picture of your install and we'll help you through this.

Chan

Easternshore Bob · Nov 28, 2011

I also have a Mini, my exhaust run is odd because it runs across a staircase before the outside wall, from back of stove goes out a T then up 3 feet through a 90 then 5 feet horizontal run to the outside, not ideal but it works. One time I had a problem with smoke an stove shut down. Problem was I was not cleaning that 90 well enough, I would shove my brush up the 3 foot section and I needed to be passing through it to clean my entire exhaust. Anyway I clean the entire exhaust every 25 bags or so.

Also clean were the vacuum switch tube connects to the stove, toothpick works for me. Also I used the foil tape on all pipe joints.

Bob

checkthisout · Nov 28, 2011

I would put a liberal amount of RTV on the connections of the inner liner of each pipe and reassemble.

If the pipe you have twists together at each joint, screws are not required.

Foil tape makes it easier to get the pipes apart in the future but it also means that your inner liner is leaking into the air gap between the inner and outer liners.

zizzlah · Nov 28, 2011

Thanks everybody! I've learned so much already and look forward to getting this right with your help. I want to focus first on the EVL values Hoverfly pointed me to. (Thank you for that link - I've never seen that info before and 3 installers/repairers didn't mention EVL, instead telling me my previous set-up was "just fine." Not according to that website. But I'm getting ahead of myself.) My new and improved installation of 3" Duravent Pro has an EVL of 3,552. Just kidding. I stopped counting at 20. Instead I did the calculations on the previous set-up, before I added the 90 and 6' of vertical pipe I thought would help! (I can see that was a mistake based on my misunderstanding of mechanical air pressure rather than draft. Thank you for that info too.) So I'll get rid of that and go back to the minimum amount of pipe I need to get up and out of the boat, aka my previous set-up.

Here's where we run into a little snag, and perhaps the root of the problem. The way I originally installed this stove (and the installation that worked fine on the old Whitfield Quest for 10 years), is 16 EVL. That install included a 90 degree tee with clean-out attached to the stove via an adapter, 3' of vertical pipe, a 90 without a cleanout, 1.5' of horizontal pipe and a cap with a screen that can be rotated to a 45 degree angle, which is where I have it. The only way I can get that installation to 15 is to raise the stove up a foot. Would that make the difference here? I guess my other option is to switch to 4" pipe, starting at the back of the stove. If I must get the EVL to 15, I'd rather build the platform as that would require less new pipe. If it makes more sense to switch to 4" pipe and leave the stove on the floor, I'll get the 4" pipe.

That's my first decision: raise the stove to get to 15 EVL, or switch to 4" pipe to give me even better exhaust. What say you?

I hear the rest of you too - caulk the life out of the inside joint AND caulk the outside including the seams on the 90s after I brush it all out. Unless, of course I'm replacing it with 4" pipe.

Finally, here are some pictures of the basics (I hope - my first time posting pix here). In your mind, delete most of the outside pipe, as it will soon be replaced with just the cap you see at the top of that vertical run. Tell me what detailed shots you want, and I'll provide them. Thanks for all your help.

Liz

SmokeyTheBear · Nov 28, 2011

Good God, Liz the EVL from the 90 degree bends alone is 20 add that 45 and it is 23 plus the 1.5' of horizontal is 24.5 plus 3' of inside vertical is 26 plus what looks like 6' on the outside brings it to 29 no good draft in that setup and likely more than a little back pressure.

That is likely the reason a lot of smoke came out, likely it came out air intake as well, and it will also go a long way to having ash pileup all over the place in the venting and ash traps in the stove.

You are just about at the limit with up and out alone (13). I vent up and out and am sitting on the edge.

DexterDay · Nov 28, 2011

Remember. If you seal the inside seam. The pipe will be Very Hard to take apart (may be impossible). I dont think you should have to do the inside. If you do all joints and all facorty seams, then that will stop the smoke. I have used a High temp anti-seize on the inside of the joints. Helps to take it apart and also acts as a barrier for the smoke.

You can do the inside. Just make sure you can still clean all your vent without the need to take anything out. Also. Dont do the caps for your clean-out T's. Just some tape or a thin layer of silicone (thin/just enough to do the job).

Without counting the cap (Was told on here cap dont count) I get 14.5 for your EVL. 5' for the cleanout T, 1.5' for your 3' of vert, 5' for your 90*, and 1.5' for the 1.5' of horiz.. 5+1.5+5+1.5= 13 dont count the cap

zizzlah · Nov 28, 2011

Fire God, this is why I stopped counting at 20 and am going back to up and out, which I calculate at 16. The stove exhausted smoke even before I added all that pipe though, so I want to get this right this time. This will be the 4th time I've installed or had this stove installed. Beyond tired of dealing with it.

I'm going to build a 2' platform for the stove, and use 3" pipe which I will actually seat and seal at every seam inside and out. That should get me to 14, which I am more comfortable with. I'll let you know how it goes.

checkthisout · Nov 28, 2011

I would leave your setup the same and simply seal the inside of the pipes better. You have enough clean outs to make cleaning easy without ever having to take the pipe apart (disassmbly is impossible once you RTV the inner liners) but who cares?

I would do that before buying another $1000.00 worth of vent pipe.

If EVL is thought to be an issue, you can test by letting the stove run for a few minutes then taking the cap off the bottom of the clean out on the outside and seeing what the smoke wants to do.

checkthisout · Nov 28, 2011

Liz W. said:
Fire God, this is why I stopped counting at 20 and am going back to up and out, which I calculate at 16. The stove exhausted smoke even before I added all that pipe though, so I want to get this right this time. This will be the 4th time I've installed or had this stove installed. Beyond tired of dealing with it.

I'm going to build a 2' platform for the stove, and use 3" pipe which I will actually seat and seal at every seam inside and out. That should get me to 14, which I am more comfortable with. I'll let you know how it goes.

Just read this.

I would just seal up your pipes with a liberal amount of RTV on the inside liner.

Raising your stove up off the floor is a lot of work and makes more heat up high rather than down low where you need it.

The last trouble spot tends to be the clean out cap off the back of the stove. Is your "Pellet vent pro" with the orange o-rings on each joint?

MarkF48 · Nov 28, 2011

For what it's worth I have the Duravent pipe and caulked all the seams and joints near the stove. An upper 90 deg elbow away from the stove is sealed with high temp tape. No leaks or smoke odor in the house. On the cleanout cap on the Tee I have a strip of silicone gasket material fastened on with an O-ring clamp to seal that joint (this wasn't installed when the picture was taken).

DexterDay · Nov 28, 2011

Liz W. said:
Fire God, this is why I stopped counting at 20 and am going back to up and out, which I calculate at 16. The stove exhausted smoke even before I added all that pipe though, so I want to get this right this time. This will be the 4th time I've installed or had this stove installed. Beyond tired of dealing with it.

I'm going to build a 2' platform for the stove, and use 3" pipe which I will actually seat and seal at every seam inside and out. That should get me to 14, which I am more comfortable with. I'll let you know how it goes.

No need for the platform.

You are below 14' now.
90* and Clean-outs = 5' you have two of them, so 10' there
1' of vert = 1/2 ft Evl, so your 3 ft of vert is 1.5'
1' of Horiz = 1' so your 1.5" = 1.5'
10 + 1.5 + 1.5 = 13'. Which should be fine. Like Checkthisout said, if you dont ever need to take it back apart, seal the insides. If you do, then seal the outside well and check it. Either way, the stove will be much happier now thats its EVL is in spec and the stove is clean..

imacman · Nov 28, 2011

Liz W. said:
Fire God, this is why I stopped counting at 20 and am going back to up and out, which I calculate at 16. The stove exhausted smoke even before I added all that pipe though, so I want to get this right this time. This will be the 4th time I've installed or had this stove installed. Beyond tired of dealing with it.

I'm going to build a 2' platform for the stove, and use 3" pipe which I will actually seat and seal at every seam inside and out. That should get me to 14, which I am more comfortable with. I'll let you know how it goes.

Liz, I would not even bother raising the stove....it's fine where it is.

IMO, you should just remove the outdoor vertical part, and attach the end cap to the piece coming through the wall. That should get you an EVL of approx. 15-16, which is just fine with 3" pipe.

Then sell all the outdoor vertical pipe, double cleanout T, and horizontal piece on Craigs list.

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