Thunderbolt Display disturbs me by a (fan) noise

Hi, I've bought 27" Thunderbolt Display and I have a problem with noise coming from my TH display. All is ok till some sound is started (for example when incoming email and there is a sound which plays always when email is received, then some noise (looks like fan) is disturbing me for 30-45 seconds. I dont know what to do, is there any solution or is it necesssary to claim it ? Thanks.