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Harmon Advance, Excel pipe, and smoke

Post in 'The Pellet Mill - Pellet and Multifuel Stoves' started by Alan, Oct 17, 2008.

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  1. Alan

    Alan Member

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    After fighting all sorts of smoke-leakage issues using Duravent pipe on my Harmon Advance, my dealer just swapped out the Harmon pipe for Excel.

    The setup is simple: at the output of the stove, which is 3 inches, a 3" to 4" Excel Stove Adaptor Tee was installed (3PAT4). The bottom of the tee is sealed up, but can be removed for cleanout by removing 3 screws. The from the top of the tee, which is 4", a strait-up vertical run of 21 feet of 4" pipe was used to go up through the roof.

    The tee is leaking smoke badly -- both from the bottom where it's supposed to be sealed, and the top, where it interfaces to the rest of the 4" pipe. I'm not sure if it's also leaking from the tee-to-stove 3" interface -- if it is, it's less than the other two leaks.

    Anybody have experience with this tee? The alternative for Excel is to use a strait 3" stove to 4" pipe adaptor, followed by a 90 degree 4" elbow -- but that means the stove sits almost another foot into the room!

    Thanks, Alan

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  2. flashbang

    flashbang Member

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    Sounds like to me being that I have used and installed excell pipe with a 3 inch tee, that the installer damaged/ripped the silicone o-ring in the tee and did not use enough high temp. silicone on the female end to the stove. I filled the gap on the female end all the way with silicone and screwed the pipe adapter to the exhaust of my Advance with no leaks at any joints with this one being the only silicone used at.
    Did the installer use liquid dish soap on the o-ring seals like the manual states before they were mated? If not it is very easy to rip it without knowing that it is ripped.
  3. Alan

    Alan Member

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    Yes, the installer did use liquid dish soap on the silicon O-ring.

    I think the problem may be with attachment of the pipe adaptor tee to the stove. The installler did fill up gap of the tee with high-temp silicon, then pushed the tee on the exhaust port of the Advance. They then drilled 3 pilot holes through the tee & exhaust port, & screwed in stainless steel screws. When screwing them in, two heads actually broke off & the "stub" was covered with silicon.

    One problem is that the exhast port of the advance is cast iron -- very hard -- & pilot holes are necessary. Perhaps the hole weren't large enough & there was too much friction as they were screwed in.

    Today I removed the fly-ash pan & internal cover so I could look at the exhaust port from the front. Looking down the port, I could see the thermostat in the hole, the interface of the inside of the adaptor tee, the screws coming throught the inside of the adaptor tee, the rear of the tee, etc. One of the screws did NOT go through the inside of the adaptor tee, but rather just pushed it in, leaving a gap between the outside edge of the inside layer of the adaptor tee and the inside edge of the Advance exhaust port. In the gap, I can see some silicon, but there may be some places with no silicon or displaced silicon...there is no way to tell. Perhaps that's the cause of the leak, at least on the bottom? If smoke went between the layers of the tee, can it get out the seal area?

    Flashbang, did you drill pilot holes & what size & length screws did you use when attaching the tee to the stove? Also before attaching the tee to the stove, how well did it fit? There seemed to be quite a bit of "wobble" with mine -- that's why the installer tried to really fill up the gap in the tee with silicon.

    Thanks, Alan
  4. flashbang

    flashbang Member

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    Yes, I drilled two holes a tad smaller then the supplied excel screws and cut them with pliers so they wouldn’t go into the inside pipe. The fit was tapered on the Advance exhaust so a light tap on the adapter and it was set snug.
    I believe your issue is with the holes in the inside pipe allowing smoke to escape between pipe walls then ultimately outside the pipe. Insist to have your installer install a new Tee at his expense since they are not cheap.
  5. GVA

    GVA Minister of Fire

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    Harman doesn't make pipe.....
    Glued and screwed at the exhaust tailpiece works but nearly impossible to get apart without ruining the pipe....
    you can screw together and then use high temp silicone tape or foil tape.......Not the 200* foil tape from the home cheapo.... true high temp 500*+ all other joints siliconed..
  6. crausch

    crausch New Member

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    Alan,

    I just found one more thing you should double-check. I have the same setup on my Advance with a 'T' right off the stove exhaust pipe. When I fired it up I had smoke coming up from the 'T'. I thought that maybe I had not siliconed it as good as I thought. I removed the two back panels (4 screws) and inspected around the pipe with a flashlight to see if there were any traces of where the smoke was leaking out. What I found surprised me. The three bolt exhaust flange only had two of the bolts tightened from the factory. The bottom bolt had only been started a couple threads and never tightened.

    I am sure this was just an oversight and probably not a common problem, but it would not hurt to make sure the flange is secured with all three bolts so that the gasket behind the flange is properly sealed.
  7. Alan

    Alan Member

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    Thanks, cjr.

    To my installer's credit, he acutally replaced the cast iron exhaust piece, along with the gasket. So that's not the problem.
  8. Alan

    Alan Member

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    FLASHBANG -- Did you get my PM?

    Thanks, Alan
  9. flashbang

    flashbang Member

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    Alan
    Yes, sent PM to you.
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