Wood Fired Water Furnace

[rubicon1]

Hey everybody,

I was hoping the experts on this site could help me with a plan I have!!

I got a wood stove given to me from a buddy that used to use it to heat his home. It looks like a regular wood stove but it has a hot water coil in the top made out of 1" copper pipe that makes loops through it. They used it to heat their 2000 sq ft. house with radiant baseboard heat for years. My

My question is can I hook this to my in floor radiant PEX in-slab?? I don't see why it wouldn't work like an outdoor wood boiler just on a smaller scale. What do you think?? The only problem I forsee is that it would be a pressurized system with not a lot of water volume. So if the slab didn't call for a heat for a long time would I potentially boil over?? The damper is a mechanical one that when it heats up to a certain point in kind of closes!! I don't think that it is thermostat controlled but I am not completely sure. Any help or suggestions would be great!! I know the information potential on this site is great!!

The reason I was wanting to do this was that it would cost effective for right now and then I would be able to switch over to a EKO later and it would be an easy swap out. Maybe I could add storage to the stove and run it wide open for the entire burn??

Thanks for your help!!

Luke

 

[cguida]

How would you make sure that the water going from the stove to the pex pipe never got too hot? I understand that the water in pex shouldn't be much more than 100 degrees, whereas baseboard water can be 170 or higher.

 

[Fred61]

There are too many chances for disaster here. You should have a side tank with enough volume to store whatever heat the stove makes. Like an old water heater.

 

[Paso]

The pex pipe I bought is printed on the side with operating temp 180 degrees

one of my systems has temps in that range for 5 years now no problems

 

[cguida]

Wow! I didn't know Pex was good to 180 degrees (and maybe beyond).... shows how out of date I am. Now I wish I had used 1 inch Pex instead of 1 inch copper for the tank connections. Would have been maybe easier and cheaper.

 

[Paso]

This is my old set up but the water off the bottom off the boiler as per the gauge in picture is 180 degrees and has been as hot as 200 I believe there is a huge safety margin built in the printed 180 on the pex IMHO

 

[rubicon1]

Can anyone else help with this situation. I would think the setup would be very similar to an EKO except without the EKO. Any ideas?? Someone please help!!

Bump

Luke

 

[akwood]

just built something like this ithink. my stove is about 5' tall and the top half is taken up with a steel boiler coil which contains about 200' 1" pipe. have only used for a week or so with excellent results. i would stay away for a pressure system. the water heats up much to fast and steam can be very dangerous. just to try it out for now i'm plummed into a 55 gal drum. it takes a large circ pump to get water thru it fast enough so it doesn't turn into steam. from the drum i have another circ pump to unit heater and eventually to radiant floor. works way better than my commercial owb. i used aquastat hooked up to induction fan to control fire and water temp. i would just stay away from pressure system.will post pics someday when i have time

 

[4acrefarm]

Regarding your coil in stove, radiant plans, I built something similer. I have 5 ss tubes running though a barral stove kit. The water is tempered or stored in a 275 gal clean oil tank. it is then run through a mixing valve (120) to the radiant floor. This is a pressurized system. I know about safety concerns. These are the steps iv'e taken.

multiple temp and presure gauges
welded braces in tank
30 lbs pressure relief valve
17 gallons of expansion

Most importantly constant vigilance, and weeks of watching and learning.presure ranges between 5 and 12 pounds no matter how hard i push it.

The boiler will thermosiphin without power. it will store some heat for night time use and wil keep 3500 sq ft comfortable in all but the coldest weather. At zero or below I have to cheat and use oil. This system works reasonably well but requires lots of time. It cost less than $600 to build and is only temporary. Some day I want to have a gasifier-solar system and lots of storage
Your idea should work but there are safety issues to consider.