Sears Wood / Coal Boiler for Pool Heater - Potential Rust Problem?

[jimingreen]

I have an unheated pool and want to eventually do solar but I'm not seeing that in the budget for this season. I have been watching Craigslist for used equipment options and found an antique Sears wood / coal boiler that the previous owner has used to heat his pool. I bought it for $60 on a whim.

He claims it works fine but that it puts out rusty water for a couple minutes if it sets for a couple days without use. He would just waste the rusty water and then when it runs clear, he would send it to the pool. He says he never had a rusty water problem and never used any sequestering agents.

Anyone else do this before? Am I asking for trouble here if I plumb this into my system?

 

[duraleigh]

YOu don't list your pool size but that heater is not capable of heating any pool other than perhaps a 6' wader. The btu's required to heat a pool are astronomical and I can tell you that heater won't provide them.

 

[jimingreen]

I realize it is way undersized. My pool is about 25k. My best guess by looking at other wood burners is that it puts out maybe 50,000 btu. This thing is probably 1/6 of the recommended size but using a solar cover to heat a pool to comfort level in Ohio just takes forever. It was July before it was even a usable pool and it still never got to what I would call comfortable.

Other than the size, am I way off base considering this? What about the rust issue?

 

[danpik]

My first fuel powered heater was a 45,000 BTU sidearm water heater (you will have to have some serious years to know what one of those is) running on propane. Way too expensive but did work somewhat. I then went with a steel jacket house boiler. First on propane, then Nat gas. Heated well at 150,000BTU but, I had to do the same thing when starting it to keep the rusty water out of the pool. I figured that after it was running there would be no problems. I found out later, that even though I did not see the rust going into the pool it was there, building up over time. It really started to mess with the water chemistry a bit and I started seeing rust staining showing up. I then started to mess with water to water heat exchangers with some limited results. I finally decided to stop trying to re-invent the wheel and put a purpose built heater on it.

 

[Donldson]

It will take 208,500 BTU to raise the temperature of your pool by 1 degree. Depending on the type of wood you will probably need 1/8 - 1/2 a cord to heat your pool to comfortable levels (and even more to keep it there). So before you hook anything up, picture yourself loading half a cord of wood in to that tiny firebox.

 

[jimingreen]

Good advice everyone. I'm sure there is an antique collector that will get more enjoyment out of this than I will.