Tom,
The majority of the original problem was due to the bottom awning sill plate on two four stacks on either side of a rock fireplace/chimney (awning on the bottom, two 4x6 picture windows with a custom trapezoid on top). These awning window sills had no overhanging lip so the installer apparently just nailed brick molding onto the sill. Maybe he caulked it maybe not, in any event the joint between the sill and molding failed allowing all the water coming off the windows to drain directly into the wall. In addition to this major leak, the other windows in the stack would occasionally (during a driving south rain) drip inside. In addition to the leaks, all the Heat Mirror glazing on
*all* of these windows failed causing fogging. (In addition to these we also had one east facing patio door and two south facing double hung glazings fail.)
Hurd covered the replacement of the failed glazing but wanted to charge labor for installing the replacements. I gave them the choice of waving the labor on the glass replacement (had facts of a lawsuit on other Hurd glazing failures) or paying for the rot repairs. They chose to wave the replacement labor.
As part of that major rework three years ago, I custom made one-piece bottom sills for the awning windows which did stop the major leakage into the wall. The other windows however continued to drip.
The Hurd windows came as two sub units, the awning and one picture as one unit and the other picture and custom trap as the other. I've always suspected the field mullion between the two subunits as the leaker but was never able to point to any one spot and say "there it is!". During the rework of three years back I had noticed small areas of rot (quarter size) in the window frames at all mullions so it appears they all leaked a little. Ripping them out this year showed more rot, even in the 'new' (three year old) wood surrounding the replacement glazing. (Did I mention these were all wood units?).
Not being able to definitively find the leaks is why we jerked the things out of the wall and went with another manufacturer. Basically we rebuilt the entire south gable wall, foundation to peak, roughly 20 foot wide and 30 foot high.
So far it hasn't dripped a drop but I'll keep my fingers crossed for a few more years.
We still have all the other orignal Hurd windows and doors. Of these, six double hungs are showing signs of age (the only ones not covered by an 8 foot wide wrap-around porch). I'm considering replacing them with new construction Marvins next year.