Temps must be dropping . . .Yet ANOTHER RMND unit overhaul

ISeeDeadBTUs Posted By ISeeDeadBTUs, Nov 1, 2010 at 1:56 PM

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  1. ISeeDeadBTUs

    Guest 2.

    Well, we're {oil burner} unplugged, and the DHW is 140 °F

    My rebuild did not go to the extent of some others here. BTW, some of the rebuilds going on here look awesome!! :cheese:

    I replaced my top skin with 16 ga carbon steel sheet. I used the 2" rockwool batts, with 1" kaowool over that. I made a serious mistake in my attachment scheme. I used 1.5" wide 16 ga, bent into an "L". I had the bottom of the "L" mig'd to the underside of the skin. Then I pushed the insulation over the upright part of the "L", then bent the "L" over to hold the insulation. This scheme worked very well at holding the insulation. Unfortunately it warped the panel.

    The biggest mistake I made was on my left side panel. Not only did I fab the above mentioned insulation hangers, I also cut three access panels. I had 1/4" X 3/4" bolts welded in from the back. The extending bolts serve as studs for attaching the 2 HX cleanout panels and the 1 ash removal panel. Well, as stated above, all those welds warped the 16 ga. The effort required in removing and reinstalling the panels makes it unlikely that it will get done during the season.

    I removed the 2 90deg bends in the stove pipe. The new chimney configuration is 8" out 2' to Metalbestos cleanout "T', then straight up 4 (3') Metalbestos sections(8")


    1) Possibly due to the chimney reconfig, starting up with everything cold I got draft within 30 seconds. In the past it has taken much longer.

    2)Despite my trepidations about the insulation materials, both held up very well to being cut and handled. I got both types from McMaster Carr.

    3) The fewer weld in 16 ga the better. I would never again attempt any sort of panel directly into the 16ga. As others have already started doing, all attachments need to go into the framing.

    4)Having the insulation in direct contact (conduction) with the refractory is not the best. On the side panel, there is <3" which means I could not use the kaowool. Simple feel of the difference between the refractory area and the non refractory area of the side skin is dramatic. I believe the frame needs to be widened to accommodate 3" of insulation plus a 2" air gap.

    5)My product is fugly. There are gaps everywhere. Though I used RTV, no way is my unit anywhere near 'tight'. So, when I fired up, I was particularly attentive to temps. With the stat set at 180, the damper closes at 190. When the damper closes the water may get to say 193, but that's it. I know at least Anthony and EP have gasketed the heck out of their Setons. But I can't see where small air leaks are making these units over-temp. Heck, even my combustion chamber has huge cracks in it to allow air to be drawn in there. Still, no over temping, and it's not that cold out.

    Musings for future improvements . . .

    A) As someone else has done, sandwiching the insulation between steel seems like the way to go. I don't have access to bending equipment for anything over 24 ga, nor do I have the welding skills to put together something clean.

    B) Is it just me, or does everyone find that the refractory never has creosote on it? I noticed that even the back of the refractory, behind, on the HX side, even that has no buildup. So, as others have pondered before, we need more refractory in these things. My refractory needs replacing anyway, so I am thinking to enclose the entire smoke path in refractory. Though the HX tubes cannot (I assume) touch the refractory, the HX needs to be completely enclosed in refractory. While this will make mid-season cleaning next to impossible, I believe the heat from the refractory will not allow creosote build up. We need to find a way to get refractory over the top of the horizontal HX tubes and keep it from malforming.

    I prolly spent somewhere shy of 1 G on the GW this year. About 4 1/2 weeks of oil in the middle of winter. I would say the GW will have saved its cost in oil by April 2011.
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