Copper tube boiler manufacturers

Bob Sweet

as to how or why some manufacturers boast that their copper tube boilers can be subjected to return temp's of 105* without condensing, yet refuse to address the effects of this on the flue pipe?

Constantin

Sure...

... because they do not manufacture the flue pipe... :-)

But seriously, the ability of the boiler to absorb low-return temperatures has a lot more to do with its internal design and the complete application than the material used in the HX. For example, if the boiler is a DV model, flue condensation issues are nearly moot.

If the return temps are low only part of the time (because the radiant loop is very small, for example), then flue condensation issues may also be only a minor irritant. However, considering how inexpensive it is to add proper boiler protection, I would elect to do that on any boiler where the flue gases are not shown to be in the safe range for a given chimney type.