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indirect water heater in summer
1886 house in upstate NY. Hot water radiators in big old house.
Weil McLain boiler installed in 2002. Last year the water heater tank went and when we went to replace it, plumbers couldn't since the chimney not lined and it would violate code. So we got an indirect water heater which works well, but in the summer months I notice that some of the radiators are warm, some more so than others. Isn't there a way to prevent the water from circulating thru the house? I just want to heat water, not the radiators.