I have a recently installed Daikin A2A  mini split, one outdoor unit, two internal.

 

I have experienced living with such a system in several properties and I was expecting the normal fan noise. However in addition to that I have a significant rattling noise from the refrigerant lines. These come and go as the unit cycles. Also sometimes there is a flowing noise, as in liquid flowing in a pipe.

 

This is not what I was expecting. What is the noise?, is it normal? can it be stopped?

 

Recording attached of the rattling noise, this has the  volume boosted to make it more obvious. My phone was about 2 meters from the internal unit and for reference the normal fan noise can be heard in addition.

Sounds terrible. Would suspect incorrect refrigerant charge or a faulty expansion valve but am not a refrigeration engineer.

 

Is it under warranty? What do installers say?

Yes, it is under warranty. The installer says that someone from Daikin will be coming to assess the issue! Only problem is weeks are going by and nothing is happening.

I was interested in seeing if anyone else had this problem or knew what it was.