Had a discharge air sensor installed today on my Lennox SLP98V. The Tech installed it in 2 different places. First, he installed it in the rear of the supply duct just directly above the A-coil (see last picture, that is where it is now).
Second, he installed it on a branch duct (see pictures one and two, look for the aluminum foil tape covering the hole just above the "natural gas" yellow label on the nat-gas line.
The position over the a-coil reads a much higher temperature rise which results in the blower speed being much higher. The second location off the branch duct reads a lower temperature rise (and thus, much lower blower speed results).
Which is the correct spot that it should be installed?