This was fast – already have had a few suggestions and responses. Thank you to the responders.
One thing I did not go into was “controls” other than the economizer and this is what the responders all made suggestions about.
What could happen if a single stage thermostat was used on on 2-stage unit? Chances are, even though the unit WAS properly sized but now, because it only runs at full capacity with the single stage stat, there are times it is oversized causing it to short cycle and not properly dehumidify.
Or, being a bank, (they do keep them pretty cold), is it short cycling due to low loads at times. They have it set for a certain people load and now there is only 1 or 2 or no customers in the bank. Maybe they need hot gas bypass or a RAWAL Valve (see post on HGBP).
So many things can cause a problem only because someone didn’t properly install a system or look at the complete application.