Our first system used a 3/4" pipe in the stove, 1/2" pipe thru the pump and lower coil (closed loop) in the hot water tank.
The improvements we made on our second attempt:
We replaced the previous water pipe with a continuously sloped 3/4" pipe to 3/4" tank connections allowing for minimal resistance, easy air vent and drain (for maintenance). (See blue flex line from bottom (cold), thru double pipe in fire chamber, to red (hot) at top.)
Pros:
+ Increased flow avoids steam and voids the need for electric (pump/sensor/power).
+ Better flow and the double pipe improve the heat transfer to the tank.
+ We have radiant heat under the bathroom floor as a byproduct of limiting the excess heat in the tank. (See silver flex lines; the yellow line in the background is the Temp/Press overflow dump line that kicks in around 90C.)
We found it optimal to:
* Build the stove central in the basement.
* Install the hot water tank near the stove, kitchen & bathroom.
* Install the solar system (battery) nearby to protect it from frost.
