Hi brian,
had a job similar to this back in the summer, same thing carpet tiles ina big office, and flood from a water dispenser, looked really easy, but five visits later the problem was still there, and this was only in a small area.
Seemed as if the bitumen had damaged the surface of the tiles and there was no way it was coming off.
The water cooler firm paid up in the end on there insurance, but it was a real pain and a good waste of my time

regards
steve