Hydronic heat quiz

Yes, the Marathon is an indoor boiler, but you could put it into an insulated outbuilding or addition and hook it up to any Class A chimney. The exhaust is 7." The leaky one I'm talking about is up in Old Forge. Sitting in the guy's basement. I doubt it's going anywhere. If you happen to get up to that neck of the woods let me know and I'll arrange to have you take a look. It's basically just the pressure vessel--needs doors, draft control, gauge & PR valve & grates, but they are all available from the mfgr. It's set up for wood grates, but I think you can retrofit coal grates, also available from Marathon.

Look at the pic at the beginning of this thread, Rhonemas. That's a one-pipe steam radiator that is kicking out the btus on my hot water system as we speak.

There's a place over near Boston (Somerset MA) that sells restored old rads of all kinds. Some really weird looking units on their website. It's A-1 Plumbing Supply or some such. You ought to be able to google it. Bet they get top dollar for those radiators. Bet they wouldn't give me more than $10 for mine.

Yes, thanks. It's a USA Corp. radiator, I believe, built before 1880. When I got it it had a steam vent and one side piped. The other side had a 2" plug. I soaked it with Liquid Wrench, rapped on it pretty good with a hammer, let it sit for a couple of hours and came back with my big wrench prepared to do battle. I bent down and unscrewed it by hand. Must not have been screwed in very well. I was prepared to resort to a drill, a Sawzall, hacksaw blade and a cold chisel. That's the way to go on those old plugs if you're careful.

It kicks out some heat.

Wood is the only fuel on your list that you have a prayer of getting for free.

Just me, as usual, hawkeye. The guy I bought it from was supposed to help me get it out of his garage and into the bed of my truck, but he was conveniently not around when I showed up. His wife and three kids didn't look like they would be much help. Just a matter of prying it up a couple of planks onto the tailgate with a 2x4. Once I got it home I just reversed the process, ground off the old paint and rust, put a coat of primer and a couple coats of Rustoleum and that was about it. If you set the feet on an old throw rug or terry cloth towel, you can slide radiators across just about any tile or wood floor. The biggest problem I had was the painting, because my garage was below 50 degrees, so I painted it and then quick pulled it into the house to dry.

Thanks for the penetrating oil tip, elk. I'll make a note of that. I'm always worried about cracking the casting when trying to extract old plugs and piping from old radiators, so I'm more inclined to drill, cut and chisel if there's any doubt.

The shut-offs are gate valves with bleeders (they're called waste drains) built into the valve. You have to be sure you solder them in the right way, so that you can bleed the piping from the system up to the closed valve. I also put unions into the line ahead of the valves in case I have to take it out and vent it again. So yeah, once the rad is full of water and isolated, just fill the system up to the bleeders, close them up and open the valves. I could isolate the rad, drain the entire system and refill it without having to mess around with the radiator. That's the theory, anyway.

Thanks, fbelec. I think the black looks pretty sharp, too.

Ohhhhhh---I could do that, too. My old house had a totally gravity fed wood/oil boiler and heating system. It's the one I was telling zogboy about. Up in Old Forge, NY, the power goes out on a regular basis. No problemo--just throw a few more chunks on the fire and go to bed. That's the way the system was designed back in 1910--to work with coal. You need large diameter pipe and cast iron radiators for it to work well.

I could do it in my current house if the wood-fired boiler was in the basement instead of out in the barn. But when the power goes out, I can't pump water to the heat exchanger in the basement. Maybe when I save up enough nickles to buy that Tarm gassifier.....

Have fun at the show, zog. Tell the Marathon guys I said hi. The leaky pressure vessel I was telling you about is the 70,000 btu/hr (wood) unit with the oil backup option. A good boiler, IMO.

If you haven't checked out their website, I think most of the basic specs are listed. They should probably update the site, lol, it's still pimping the Y2K fiasco.

They sent me a pdf pricelist, but I think it's on my other computer, if I saved it at all. If I can find it I'll send it to you. If not, you can email tarmusa.com and they'll send you one.

Basically as I recall, they range from about $4,000 to $10,000, delivered. The cheaper ones are old tech, I think, but perfectly good boilers. The thing that put me off was not the pricing, necessarily, but the recommendation that you add water storage, to the tune of about $3,500. There are some real advantages to water storage (flexibility and efficiency), but the things should work just fine without it, too.

I'm looking forward to hearing what zogboy thinks about the Mararthon. When I bought mine I thought it was a Tarm knock-off, but that's not really fair, considering that there's nothing fancy about the technology, and Marathon has some interesting innovations. The Marathon is designed to run hot to achieve secondary combustion and cut creosote and emissions. I tried to keep mine between 190 and 220.

I've been thinking about what it would take to build one of these, but you get into issues relating to closed loop, pressurized systems vs. a heat exchanger arrangement as josh described so well in the previous post. Heat exchange coils suggest to me that it's an open system, which means more expensive circulators, piping, water treatment, etc.

I think it would be easier in the end to use a pressurized, insulated tank from which you drew water to the various zones as needed. I'm thinking maybe two or three big-ass (say 250-gallon) water heaters, all piped together. I thought about fuel oil tanks, but I'm not sure they're rated for pressure and would require some serious insulation. Water heaters, on the other hand, are built to withstand much higher pressure, are tapped for conventional hvac piping, PRVs, etc.

I don't even know if anyone makes a 250-gallon water heater, but that would be the ticket.

In one thread Craig suggested adding a mixing valve to a wood-boiler system, essentially using the water in your radiant heat system as storage. That would probably work pretty well for someone like me who has an old house with lots (like 15) big, cast iron radiators. A reverse circulation scheme like that with continual circulation would probably work really well. If you've got baseboards, on the other hand, then mabe some sort of storage tank makes sense. But not $3,500 worth of sense, IMO. The boiler should work just fine all by itself. At least the ones I've owned always have.

Yes, I understand the rationale behind the storage tank. I just think it's a lot of money to pay for convenience.

What I envision has nothing to do with coils or heat exchangers. You just pipe the boiler directly into the storage tank(s). A circulator sends water between the tank and the boiler. It would be like having a boiler with a 500-gallon water jacket. You might need a coil for your DHW. Currently, I have a sidearm heat exchanger connecting my hot water heater and boiler. Return water is routed through the heat exchanger on its way back to the boiler, and gravity circulates DHW between it and the hot water heater. I can explain that better if you don't understand what I'm suggesting.