I am an inspector in the Seattle WA area and I have been seeing a lot of Hydronic heating, especially in tall townhomes. They are using the same water heater tank or tankless as the domestic water source. The heating system kicks out great heat and works great. My question?
I though that boilers and/or hydronic heating has to be a closed system, separate from the domestic water source used for showering etc… All of the water heaters being used that I see appear to be just a standard water heater. Maybe I am wrong though.
Is a specific water heater supposed to be used for this to keep a closed system? And if so, how do you tell if it is one?