Be smart and use two separate systemsmany moons ago they
had system combine when they use the coal.
I don't know if they make those this days.
Tony


"Bob" wrote in message
...
My house, built in 1956, needs a new heating system boiler. It's as old as
the house.

I've seen some models that have domestic hot water (DHW) capability - are
these worth getting? It seems to be a waste to turn on a boiler rated
50,000-250,000 BTU for hot water in the dishwasher.