They say the flue combustion gas will condense and corrode a Cast Iron
Heat Exchanger if the water return temperature is below 130 deg
Farenheit, and they adjust this temperature using a piping bypass and
when the boiler's outlet temperature is say 150 deg Farenheit.
But then they say the circulator pump starts immediately....so that
doesn't make sense since the outlet temperature will not have reached
150 deg Farenheit and therefore the water return temperature will be
BELOW 130 deg Farenheit???
Why won't this cause corrosion since the return temperature will be
below 130 deg. Farenheit and the burner will be running so the
combustion gas will contact a colder return water temperature heat
exchanger surface and should logically cause condensation and