My backup heat has been fuel oil, but I've been facing two problems: the oil boiler is almost 25 years old and has not improved with age, and I last bought fuel oil in 2007 and I'm almost out.
I bought a Takagi TK-50 jr instant-on propane hot water heater a couple years ago, and it's finally installed. I have it plumbed in parallel with the wood, oil, and storage (see diagram below). It's capable of providing hot water at 182 degrees, and is rated for space heating. It's appears to modulate both the combustion and the flow through the HX to hit its target outlet temp.
I'll have to do some real testing. In a brief inaugural firing, it heated 72 degree water to 180 degrees at about 2gpm. We'll have to see what it does with more typical inlet temps. The HX provides a LOT of flow restriction, so I expect that it will be flow limited. Updated plumbing diagram:
I bought a Takagi TK-50 jr instant-on propane hot water heater a couple years ago, and it's finally installed. I have it plumbed in parallel with the wood, oil, and storage (see diagram below). It's capable of providing hot water at 182 degrees, and is rated for space heating. It's appears to modulate both the combustion and the flow through the HX to hit its target outlet temp.
I'll have to do some real testing. In a brief inaugural firing, it heated 72 degree water to 180 degrees at about 2gpm. We'll have to see what it does with more typical inlet temps. The HX provides a LOT of flow restriction, so I expect that it will be flow limited. Updated plumbing diagram:
![Finally got propane backup installed Finally got propane backup installed](/talk/proxy.php?image=http%3A%2F%2Fhome.vecs.org%2Fassets%2Fimg%2Fplumbing-diagram.gif&hash=ec912d38fbb381f72ae73b9f2e76d5d8)
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