Thanks both of you for your detailed answers.
I too suspect that the fan circuitry is not working as it should, I have already mailed Antec and I am waiting for a response from them. I have been touching the PSU and it is hot, but then I guess PSUs do get hot. I'm not sure how hot is too hot 🙂 I don't think it is because i am not using enough power, the setup is a Athlon64 3500+ and overclocked 6800 GT, two SATA hard drives.
Interesting that it takes so long for them to RMA, maybe i should return to the place I bought it for a new and let them take care of it. Very annoying to buy a brand new quality? PSU and for it to arrive with a major failure, lots of hassle to unbuild the system 🙁
Thanks for your advice..