Toshiba VRF cassette fan noise

[glenn1340]

Hi guys,

I`m commissioniing a Toshiba VRF system with five cassetess and seven high wall units. The system has been set up ok with the help of the Toshiba technical help line but two of the cassette`s fans are very noisy even at minimum speeds. A phone conversation cannot be easily made sitting near them and the draught from them is uncomfortable. I`ve checked the ceiling setting and all`s ok there. I spoke to Toshiba and they confirmed that the settings were right for the ceiling in question. But here`s the strange thing two of the othere cassettes are a more powerful model and they are very quiet. The models giving the problem are MMU-AP0362H.

Toshiba have siad it`s not possible to reduce the speed any more as to do so would could freezing of the evaporator, but as say the larger ones are virtually silent with no freezing problems .
I`m just wondering do any of you guys know of a way to slow the fans down.

Cheers guys,

Glenn

[The Viking]

Is there any fresh air introduced through these cassettes?


.

[Mach 2]

Have the cassettes been installed level,even slight changes from the vertical of the fan shaft can cause in-balance and vibration.
Also look at the way the units have been secured to the building structure as this can amplify the effects of vibrations etc.
regards Mach 2

[Loops]

Hi Glenn,
Is the noise excessive air movement type or a 'growly' electrical motor noise?
If the latter check the blade is tight onto the shaft.
About 3-4 years ago Toshiba changed motor suppliers. The new motors came out with wrong spec distance between the fan 'stop' and the securing nut on the shaft.
This caused a weird electrical winding hysterisis type noise but in fact was a loose blade. Tosh did supply specical washers to compensate.
OK this was a few years ago and on the small bodied 4-way cassettes only but in principal it's worth checking.
Cheers
Loops