High Efficiency Furnace

[Paul Ventre]

What is the least likely point of failure in the heat exchanger of a high-efficiency furnace?
a: bends in the chamber
b: areas where air flow through the chamber is restricted
c: along longitudinal welds
d: the connection point at the exhaust collector

Can anyone help me answer this question? Thanks:confused:

[David Bell]

The longitudinal welds would be the least likely to fail as they are not subject to the acidic moisture of the flue gasses.

[Gunnar Alquist]

What is the least likely point of failure in the heat exchanger of a high-efficiency furnace?
a: bends in the chamber
b: areas where air flow through the chamber is restricted
c: along longitudinal welds
d: the connection point at the exhaust collector
Can anyone help me answer this question? Thanks:confused:

Paul,

I think that you are going to have a hard time finding that out from a bunch of home inspectors. You really cannot see into the heat exchanger of these newer furnaces unless the exchanger is removed (something that a HI does not do). In the older furnaces, the areas that I saw damage was down near the burners, where the heat was the greatest. But, the upper sections are not visible from below, so there may be damage that cannot be easily seen. Also, I have seen in the Carrier family of heaters (the older ones, at least), the spot welds at the dimples often fail, which is a potential breach in the heat exchanger.