Thanks for that wonderful reply.

Water returning back to the chiller is at approx 13C. The building is reaching set points via the fan coils. I dont think the chiller flow temp could be reduced any more as its quite an old chiller now and there are lots of problems with it at the moment such and PCBs have just been replaced but been told if it fails again parts are obsolete.

The set point of 21C has been running for the last hour. Humidity is at 71.3% and supply temp now at 22C doesnt seem to be dropping but I reckon it will be recirculating quite a lot of the building air now rather than bringing in lots of fresh air due to the higher set point.