Strange sound from radiator, just had new central heating system (combi condenser boiler) put in, problem?

All radiators are new (inc.new boiler). Only one radiator in 2nd bedroom makes 'crackling sound' when heating up, and also a sound like when you fill a gl bottle up quickly and the water is reaching the top. None of the other radiators make these sounds, could this be because of a problem? Would it be reasonable to ask the company that installed the new system to check it out?