pellet steam boiler

[mojito]

we are looking for a pellet steam boiler to replace our oil boiler. we are having trouble finding a unit. we find pellet furnaces, and even pellet hot water boiler but not steam. is it because the pellets dont get hot enough? we really hate to redo our old steam radiator heating system in our 1930 house. any suggestions?

 

[Redox]

I suspect that there would be too much of a problem with a dry fire on a solid fuel steam boiler. Your boiler has (or should have) an electrical low water cutoff to kill the burner instantly in the event of a low water situation. Putting out a pellet fire fast enough may present a problem, but I am just speculating here. It is also a very small niche market for small steam boilers these days.

It is possible to repipe your system for hot water using the existing radiators, but it will be dependent on a lot of factors such as whether you have added insulation over the years. A good hydronic tech will probably be along any minute now.

Chris

 

[Sting]

think coal - it makes great steam

http://nepacrossroads.com/forum-82.html

 

[BrownianHeatingTech]

we are looking for a pellet steam boiler to replace our oil boiler. we are having trouble finding a unit. we find pellet furnaces, and even pellet hot water boiler but not steam. is it because the pellets dont get hot enough? we really hate to redo our old steam radiator heating system in our 1930 house. any suggestions?

Other than converting to hot-water heat, not really. Residential steam heat is such a niche market that there really isn't a financial incentive for manufacturers to develop pellet-fired steam boilers.

In renewable fuels, the only real current options for steam systems are things like biodiesel and waste-vegetable-oil.

i think any boiler could be adapted to a steam boiler with a water level control valve which keeps the boiler full to a certain level & any heat rise involves the steam delivering the heat to the radiators instead of a pump.

No, only some boilers are dual use. The pellet-fired hot water boilers on the market are hot-water only. The reasons Redox gives are a big part of that - a solid-fuel fire doesn't just "switch off" in a low-water event.

Joe

 

[BrownianHeatingTech]

shouldnt the auto water level valve compensate for that + expansion tank?

The water level control shuts the burner off. With an oil or gas burner, that means the flame ends. With a pellet burner, that means the flame slowly dies down over the course of some minutes. That means the boiler is going to continue to boiler significantly beyond the low-water point.

Joe

 

[BrownianHeatingTech]

shouldnt the auto water level valve compensate for that + expansion tank?

The water level control shuts the burner off. With an oil or gas burner, that means the flame ends. With a pellet burner, that means the flame slowly dies down over the course of some minutes. That means the boiler is going to continue to boiler significantly beyond the low-water point.

i think i saw water level control which maintained water level of boiler. automatic waterfeed not available?

You don't want to be feeding water in while the boiler is still boiling. It makes the level surge, which makes accurate control impossible. Proper controls have a time-delay built into them for that purpose. The boiler would run dry if the time delay was long enough for the pellet flame to go out (not to mention that it would then not relight once the water had been refilled).

Joe

 

[Eric Johnson]

No wood-fired steamers that I'm aware of--not even in Europe. Sad, but true. Gary Switzer might custom-build one for you.

 

[webbie]

I've sold hand-fired coal steam boilers, which worked fine - so the problem is probably as Joe says - niche market, not worth the while.

Folks should understand that the market for Pellet boilers was non-existent 5 years ago, and extremely tiny even one year ago.......it is mostly in reaction to high fuel prices of the last couple months. There is no telling as to whether even that market is sustainable (based on the 10+ makers entering the fray).

 

[mojito]

Thank you everyone for the good advice. One question for Redox, how much (ball park) should it cost to re-do our house from steam radiator heating system to forced hot water - using the same radiators?

thanks!

 

[Sting]

First - ask if we are converting a one or two pipe steam system to hot water

If one pipe == well you have a lot of new pipe to run - then too - maybe the radiators are propitiatory to steam and will not flow hot water

Lastly - the system was sized for steam radiation - with hot water, the load will out weight the new available btu"s

Steam boilers are always receiving make up water = How else do you make more steam????

Come on folks - if you don't know - please don't post bad advice for the sake of posting!

 

[heaterman]

Thank you everyone for the good advice. One question for Redox, how much (ball park) should it cost to re-do our house from steam radiator heating system to forced hot water - using the same radiators?

thanks!

It's as much a question of your piping as the radiators themselves. You would need to have a two pipe steam system in other words a pipe for steam supply and condensate return. The next thing is if the castings on the rads connect with each other on top. Some steam rads are for steam only and can't accommodate hot water. If the piping is suitable and the rads are the right design the system will definitely need to be cleaned and flushed before installing a new boiler of any kind.

 

[BrownianHeatingTech]

maybe a small storage tank?

Water seeks its own level.

Thank you everyone for the good advice. One question for Redox, how much (ball park) should it cost to re-do our house from steam radiator heating system to forced hot water - using the same radiators?

There will be a few factors:

1. Are the existing radiators large enough? Steam is 212 degrees, whereas a hot water system typically operates at 180 degrees or less. So you get less heat out of the same radiator. If yours are oversized (which is the case in probably 90% of systems), it's not a problem. If they are undersized, then they would need to be replaced, or some extra radiators added.

2. Is is a one-pipe or a two-pipe system? Most steam systems are one-pipe, which means that a second set of pipes needs to be run. Some are already two-pipe, which greatly simplifies things.

3. Are there contractors near you who are familiar with steam-to-water conversions? I would suggest calling around and asking heating contractors. Tell them specifically that you want to convert from steam to hot water, and ask if they are familiar with what is needed. Ask for references for conversion jobs (not just other heating jobs). Don't bother asking about the pellet boiler as a heat source, at that stage - if necessary, you can have one contractor do the conversion, and another do the heat source.

Joe

 

[BrownianHeatingTech]

Looks like three of us replied at almost the same time!

Joe

 

[heaterman]

First - ask if we are converting a one or two pipe steam system to hot water

If one pipe == well you have a lot of new pipe to run - then too - maybe the radiators are propitiatory to steam and will not flow hot water

Lastly - the system was sized for steam radiation - with hot water, the load will out weight the new available btu"s

Steam boilers are always receiving make up water = How else do you make more steam????

Come on folks - if you don't know - please don't post bad advice for the sake of posting!

All valid points!

I would probably consider first if the piping and rads can be used with hot water, then do a heat loss calc on the house (mandatory in this situation) and finally research the EDR of all the existing rads to see if they'll provide enough heat at 170-180 instead of 215*. If the stars align on those things, you're basically good to go with the switcheroo.

 

[Redox]

I defer to the experts on hot water questions; I am more of a hot air guy!!

I never implied that it would be a cakewalk, but it is possible with expert advice and guidance. There's a good chance you will find some in this forum.

Chris

 

[renewablejohn]

mojito

If you want steam from a woodchip or wood pellet stove I would suggest connecting the stove to a Thermal oil boiler and then using a steam evaporator to produce your steam. It is the same technology that we are using to power our conventional steam engines.