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I have a Central Boiler 2400 OWB which I will install in new construction, 1200 sq ft main floor radiant in joists and 1200 sq ft basement radiant slab. Total house heat loss 60K worst case. Considering indoor boiler back up to OWB with indirect fired HWH. I would like to use a DHW heater for my back up "boiler" in series (no heat exchanger) with my OWB. Considering using a David White 75 gal, 75K btu TTW2. Questions:
Will the TTW2 handle the 185 degrees water from the OWB? If not, are there DHW heaters that can?
Can a DHW unit operate in tandem with the atmospheric pressure system of the OWB?
Will propylene glycol antifreeze or rust inhibitors used with the OWB bother the DHW unit?