Sorry for the late post - haven't checked in here for a while. I have a double hot water coil in my Alaska stove which is hooked to my existing elec. water heater. Pretty simple operation as you just create a loop in which the cool water flows from the bottom of the WH to the bottom of the stove coil, then exits the top of the coil into the top of the WH. If your WH or storage tank is within 10' of your stove you don't need a pump as the water flows on its own but if your like me the WH is more than 10' away and I need a small pump to circulate the water. I let my pump run constantly as it uses minimal elec. or you can use an aquastat which will turn the pump on and off at pre-set temps.
The list of supplies I used is:
Coil, pump, auto air bleeder, pop-off valve, 3/4" copper pipe w/ valves and fittings, and pipe insul. The aquastat is optional.
When I start the stove in the fall I turn off the elec. to the WH. The stove heats all of my water during the heating season which saves me a bunch on my elec. bill. This is one of the best investments I've made (about 5 years ago) and I did all the work myself (not the greatest plumber either).
I got the basic hardware and instructions from Alaska and the rest of the supplies from a plumbing supply.
If you need any more info on my system, just give me a shout.