Hello everyone Im new here to this site.I hope I can help people where I can but I have a problem that I am finding hard to solve.
I installed a new Fujitsu AOT30LMAW4 muti unit with 3 heads connected to it.2 x AST12s plus a AST24.
The problem Im having is the system runs fine on cooling but on heating Im getting a harmonic noise comming through the ceiling.There is also a vibration ploblem as well with the head units vibrating on the walls .one of the pipe runs is at a max of 25 mts and im getting vibration!Why is this happening only on heating?The units are all running mech fine.pipe lengths etc are all in there perameters.Refrigerant charge 410a is fine, power is fine.Ive put loads of these systems in but this one is nasty.Its a mono pitch roof so there is no way of getting into the ceiling to check pipework but I havnt had these issues before.It has the Fujitsu techs have no answers.I can only hope that this problem may have happened to someone else here and they found the cause