Steam Heating

[dualcarbs]

Hi,

New to this forum... we have an older home with a single pipe steam heat system. It was designed to fire oil, and fired intermittently: a few minutes on to raise steam which flowed to the radiators, then a few minutes off while condensate returns through steam traps and the same pipes. I've seen pellet fired hot water systems but not a steam system, and definitely nothing designed for intermittent firing. I was thinking about a pellet burner that could have a reduction in air flow and a flue bypass, to simulate the off time of the oil burner. I'd much rather buy something that has been engineered for the purpose, than to try to design something myself. Has anyone been there / done that? Or know of anyone that makes a pellet fired steam boiler for a single pipe system?

 

[E Yoder]

I haven't. There's a lot of steam guys on heatinghelp.com if you don't find a response here.

 

[chew72]

Are there solid fuel steam boilers? I'm more familiar with larger commercial / industrial boilers but I would think with current day rules and regulations you would have to be able to 100% shutoff the fuel. What is the operating psi of a residential system?

 

[ABMax24]

If your system is designed properly the boiler shouldn't need to cycle at all. In a properly sloped and sized one-pipe steam system there is a counterflow setup in the piping, where the piping is sloped upwards toward the radiators, the steam travels through the top of the pipe, the condensate travels at the bottom of the pipe back to the boiler. This can be a continuous process and does not require cycling of the boiler to function.

I think the kicker here is finding a pellet boiler that produces steam, I've never heard of one, not to say they don't exist though.

Steam for household heating is disappearing, we spent a significant portion of trade school on steam heating, but I've never seen a steam setup in a house.

 

[chew72]

I've only come across one in all my years.
Edit: a residential oil-fired steam boiler that is, not a pellet one.

 

[dualcarbs]

Thanks for the responses! I've worked on industrial / utility sized solid fuel steam boilers, (coal, wood, bagasse, even MSW) but never home heating size. And I agree there would have to be a safety fuel shutoff. The big utility boilers firing solid fuel that keep a large inventory in the furnace (like a CFB) use an emergency feedwater pump to keep from running the boiler dry on a trip.

I haven't seen any steam producing pellet furnaces in the size I'd need. I did find some in a much larger size.

We shut the steam system down and put in a geothermal system that has been performing decently but since we still have the infrastructure of the steam system, I'd like to see if we can use it economically. The existing system is rated 240,000 Btu/hr, and runs at about 15-20 psi. I can't speak to how it was designed, more how it operates and we only ran it for about a year. The oil burner is rated 2 gph. Some of the traps are questionable, and if I thought we were going to put the system back in service I'd have them all rebuilt.

This may not be feasible, but I'll keep looking. Thanks!

 

[SpaceBus]

Maybe there are some coal fired steam systems still on the market.

 

[chew72]

You say it's designed to run intermittently. I'm just trying to wrap my head around that. If there was a constant call for heat what's causing the boiler to stop. a timer or low water? If it's low water once the system is cold I presume the boiler is full? I can't help but think the boiler should only care about providing certain PSI of steam pressure. If it's running low hot water it could use a feed water tank but then again maybe I'm thinking more commercial.

 

[gthomas785]

I grew up with a residential steam system, oil fired. If the boiler is sized correctly, it can run continuously with condensate flowing back to the boiler while firing and never run out of water. However if the boiler is too big it will over pressurize and shut down, and if it's too small it will run out of water and shut down.

I also have never seen a pellet steam boiler. I wouldn't be surprised if none existed since steam was already pretty far gone by the time pellet fuel started becoming popular.