Originally Posted by
brdad
Properly plumbed, you can use any boiler to heat or help heat swimming pool water. In fact, it is not uncommon when you have a wood boiler that there is an excess amount of hot water which can be "dumped" into a large load such as a swimming pool, large radiators or storage tank in the basement, or driveway heaters.
In most of these cases, you would want to use a heat exchanger, which isolates the boiler water from the dump load. There are wood fired boilers designed to directly heat pools without a heat exchanger, which probably work great for that purpose since they plumb directly into the circulator line with PVC, but they are not designed to heat your house as well.