If you've got your unit on - you've made sure it is producing cold air and there is water in the water tank - and there is (cool) air coming out of the unit but the room isn't getting cool, it means there's a problem with the amount of humidity in the room. This indicates there is too much humidity in the room and not enough ventilation.
To fix this problem make sure there's enough ventilation in the room by opening more windows / doors.
For any further help contact us via email at info@airconditioningcentre.com or call us at 0370 3344 556