Hi, roelescence

maybe I am wrong, but in above schematic diagram something is missing

... return hot water from HE-condenser should come into the cooling tower from the top ... that line is missing and not into the sump as is shown ....

if the drawing is correct you have just bypass cooling tower and you return the same warm water back to condenser ...

please, if possible, to recheck all piping (and upload whole scheme) to water pump/s, cooling tower, condenser, make up lines, drain lines etc ... we need a whole info to be able to help...

Best regards, Josip