I encountered for the first time today a Rinnai hydronic air handler heating system that unlike a traditional “closed” system, it shares the instant tankless hot water heater that supplies the both the homes potable water and heating coils in the furnace (heat exchanger) portion of the system when needed.
Are there any concerns such as cross contamination in the event of a supply line malfunction that should be further expanded on…? A link to the manufacturer doesn’t seem to exist. There appears to be an auto “flush” cycle every six hours to evacuate any stagnate water that may accumulate.
Otherwise it appears to be a good concept… perhaps more common in Canada or the Northeast. Not here in California.