So you have 73/76 cond h2o in & out with an 84 degree liquid temp off the cond. These machines were usually at 10/10/10 at full load. That is 85/95/105 on the liquid temps. You are showing 8 degrees delta t on leaving water and liquid ref at 60 % load. Its close but I would expect 5-6 degrees. Your thermo's accurate? Also you are only picking up 3 degrees on the water side. Again I would expect 6 at 60%.
Now looking at the Liquid temp vs cond pressure you have 84 degree liquid which shoud show about 2 psi pressure but you report 10 psi which equates to about 102 degrees.
Sooo, my opinion (remember what you are paying for it) is air in the machine causing high head pressure plus some tube fouling in the cond. The only thing saving your butt is the cold tower water which is depressing the high side and keeping you out of surge ( I presume you are not surging). The cond flow looks good.
Those tubes will only take about .0005" of fouling before pperformance starts going downhill and a machine can foul in about a week under the right conditions.
Check out the purge on this unit. What type of purge is it. Was the chiller down for an extended period of time?
The evap side looks Ok. You show making 4 degrees thru the bundle with an approach of 2-3 degrees. Check the belly temp and compare it to the evap pressure and leaving chill h2o when you get time. Single pass evaps give some different readings than you might expect.
If you are not doing it, start logging all your readings for your reference!
I saw on this post from last year on flow charts and associated DP settings (ft/hd) for Trane Chillers. I am trying to det up some DP devices for measuring flow and I cannot find the Trane Document online, I saw where you had e-mailed it to someone. Is it possible for you to send this to me as well, I would really appreciate it????