Outdoor furnace and water to water heat exchangers

I have been researching outdoor wood furnaces. From what I can see, there are 2 basic types, pressurized and atmospheric (non pressurized). A pressurized system would hook up directly to my FHW system to make a closed system. An atmospheric system would transfer heat via a Flat Plate, water to water heat exchanger. This would keep the 2 systems separate, hence avoid any contamination/corrosion issues associated with atmospheric systems. My question is, How well do the exchangers work? I realize they can't be as effective as a direct link to my FHW system, but are they close?
Also any opinions on outdoor wood furnace brands would be a great help.
Thanks,

A good heat exchanger is quite efficient and can last for a loooong time. Don't skimp. A leak between the water circuits is a BAD thing.

Anyone can recommend a brand but a good brand is one with knowledgeable installers and service personel in your area.

Currently my house under construction has a water to freon to water system. The heat pump has two freon to water heat exchangers. I am hopeful they are as trouble free as a god water to water system as you are inquiring about.

[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]

i have a global hydronics outdoor wood/coal boiler.
we have had nothing but trouble with it. we paid for a safe, working furnace. the pin on the shaker/stoker keeps sheering, and when this happens the grates spread and then it wont shake the ashes down. it won't burn coal, the air is directed above the coal instead of under the coal. this company does not stand by their products.
and i would not buy a homestead either. i have talked to different distributors and any coal boiler they have used, they have had to try many different things so that they could burn coal. they said they were not reimbursted for changing reconstructing the furnaces. they all stated they had a lot of extra money into them.