sf 250 domestic hot water set up

I believe this valve or similar would do the job placed at location "A" (three way valve). Location "B" would require a (two way valve - on/off)
One or the other, .. both wouldn't be required.

http://www.taco-hvac.com/en/products/560%20Series/products.html?current_category=111

Instead of using valves to control flow direction I would use a pair of pumps to control flow. It's then easy to control the flow by powering one or the other pump. The cost of electric controlled valves are similar to the cost of the pump. The pump system is more reliable than one based on valves plus a pump.

I don't know, but I was thinking to have the water constantly circulating and use the reverse aquastat to operate the fan in the water to air unit to dump the heat. Is there a reason why this would not work? Thank you, Craig.

It doesn't sound "typical" or efficient. For one thing, the tank temps would be continually changing, even though none of the domestic water was being used. I would get the tank water up to temp, and then leave it alone, until it needed more heat, due to use or cooling.

The tank I am going to use is a 40 gal. tempering tank it;s a brick lined tank. It will help heat water in the summer month when the stove is not burning. I am also going to piggyback through my oil burner's domestic hot water system.
It won't take long to get the water hot using a 40 gal. tank.

This is a simple question with a pretty complex answer. You might want to check this thread: Water Heater Coil

I'm don't want to rely on electric/pump systems to keep my living room furnishings from being blown into the yard. Many who do seem to add battery back up power systems for the pumps. Kinda kludgey, IMO. http://www.woodheat.org/dhw/dhw.htm

The brits never got over open thermo siphon systems, which are probably the best solution for simple 'solid fuel" DHW. It's popular there in many cottages. Here's a fair example of what they do. http://www.solidfuel.co.uk/pdfs/link_up.pdf

Yanche recommended Dan Halohan's books on the subject and here's an example of why: http://www.oldhouseweb.com/stories/Detailed/830.shtml

Besto,

- Charlie

Thanks Charlie Z I'm sure I can get something figured out.