Server sound like aeroplane engine?

You must be wonder why my office server will sound like aeroplane engine?

The server room is very small, the size is about 3m X 3m. There are 3 IBM servers, 2 PC, 1 Nokia firewall, 1UPS. All these equipments are squeeze inside the small room.

Yesterday, I heard a noisy sound (like aeroplan engin sound) came out from the server room. I thought something wrong with the servers. So I quickly go into the server room and check. Oh God! the room was like an oven, the heat can make you feel sick. The air-cond was blow out hot air, not cool air. Luckily it is not a server problem.

I feel pity with the air-cond. It has to work 24 hours x 365 days, non stop. :P