Been lurking here for a couple of seasons, thought I'd add my info and help this community grow!
3 seasons ago, my step-dad and I built a MEN style Heater out of a stubby 30 gal (I think) electric water heater and other various parts laying around. It has gone through many iterations and is still evolving, but more on that later!
This guy lives in my shop, and puts out massive heat! One of my major goals with this was to have a system that was completely functional without any outside stimuli, AKA electricity. So we opted for a basic drip system with gravity feed. This has worked well, although it does present some other issues. But, if the power is ever out for extended periods, as long as I got fuel, I'm warm!
It runs on both Motor Oil and Veggie Oil, depending what valve I open. I have a small oven thermometer on the outside that registers a max of 500F, and its trivial to make the needle go totally buried!
So after dealing with what looks to be basic issues with this guy, I have learned a lot, but haven't figured it all out. Of course fuel delivery remains one of the biggest issues. One of my other big issues that I have solved: the Soot and the Cleaning!
Before one of the more recent evolutions, we would have black snow flakes most of the time we were burning. We knew this was because the fuel wasn't burning completely, but based on the system, we were doing everything right. We would try to adjust our fuel, and it would cool too much (it really likes to keep temps up. If we are not at Full Operating Temperature, it isn't happy), so we try to adjust the air in various ways, but could never get a good burn that way.
We took a step back. Thinking harder, we decided that our biggest problem was the style of manifold. We had built a Sanders-style manifold, but without buying the book or using any plans. Basically, looking at pictures and making one. It worked, and it worked as advertised. Including the issues, such as hard startup, massive soot, constant cleaning, and regular clogging.
Most manifolds I have seen for non-forced-air systems rely on one of 2 methods: 1. Create a pool of fuel, heat and burn (basic plate method) or 2. Hit top plate, run/gas to small combustion chamber (middle), heat and burn. We took both these principles into account in design, and added the idea that the more hot metal it hits, the more spread out it will be, therefor heating, gassing and burning faster and more thoroughly. By taking 1/2" re-bar and forming grid-layers of triangles, enclosing a couple of the larger spaces to create a small combustion chamber, we created a manifold with lots of surface area yet enough space for the oil to spread and gas. Looks a little odd but....
It has worked out perfectly! We now have little to no soot, I haven't cleaned it in 5+ burns, its still clean every time I look at it, so its burning EVERYTHING. Start-up literally requires dumping ~1 cup kerosene down the intake and dropping a match down it (actually, I use kerosene soaked q-tips, cause I have a ton). Takes a bout 20-30min to get to FOT, even at 5F ambient. It burns consistent every time I use it (not so with old manifold).
I still have 1 big issue I haven't worked out yet though, and that's fuel efficiency. When we built this, we were under the impression that it should burn ~1qt/hr. Our reality is almost 1gal/hr. Seems a bit steep to me, but that's one of the reason I'm here, to ask what kind of rates everyone else gets, and if anyone has any idea why it eats that much.
The pics below are kinda old, I need to take some fresh ones. We have re-arranged the fuel lines, and found a better air-cone location since these were taken, so excuse the bit of soot left on the manifold as these were taken right before one of the last times it was cleaned. I will take some new ones soon and get em posted.
