Daikin Home Air Conditioning Query - noisy buzzing - help gratefully received!

[AHLondon]

Hello all

Any help or views gratefully received! I have just had the following units installed, brand new, from the Daikin FTXS range.:

1 x 4mxs68f
2 x ftx20j3
1 x ftx25j3
1 x ftx35j3

Every five to ten minutes of use the AC in each room makes a loud aggressive buzzing sound - a "BZZZZZZZZZZZZZZZZZZZZ" - for up to 30 seconds or so. We are not sure why this happens or to stop it happening but it is loud enough to wake us and our daughter.

I can't attach the file here but have uploaded to http://vocaroo.com/i/s1SuWNp5Epj1.

Is this normal? Is there any way to stop this? We were reassured several times when discussing models to consider that the AC would not be audible. I am honestly surprised therefore to be told that this is normal and to not have been warned.

Many thanks in advance for any help gratefully received!

[The Viking]

OK,
Not able to hear your audio file clearly but I don't think that will affect my conclusion.

What you are hearing is (most likely) not the AC units themselves but rather the condensate pumps the installer has fitted to them.
Your installer should be able to sort this. First thing to check is that the pumps are fitted in accordance with manual and not touching anything else as vibrations transferred = noise amplified. (To recreate this noise and to prove that it is coming from the condensate pump you can remove the filter from the AC unit and pour a small amount of water, ~1/2 cup, on to the coil).
If your existing pumps can't be made to be quiet enough there are plenty of other options available, best in residential situations is gravity - just a pipe downwards to a drain but unfortunately this is rarely possible unless the AC unit is fitted on an outside wall. Looking at pump options instead, there are pumps which only would start once per day and there are also pumps that can be fitted remotely, away from the indoor units.
But the starting point is to ensure that the pumps you got is fitted in accordance with manual and best practices. (Anti-vibration, foam, pads can also help)

[AHLondon]

OK,
Not able to hear your audio file clearly but I don't think that will affect my conclusion.

What you are hearing is (most likely) not the AC units themselves but rather the condensate pumps the installer has fitted to them.
Your installer should be able to sort this. First thing to check is that the pumps are fitted in accordance with manual and not touching anything else as vibrations transferred = noise amplified. (To recreate this noise and to prove that it is coming from the condensate pump you can remove the filter from the AC unit and pour a small amount of water, ~1/2 cup, on to the coil).
If your existing pumps can't be made to be quiet enough there are plenty of other options available, best in residential situations is gravity - just a pipe downwards to a drain but unfortunately this is rarely possible unless the AC unit is fitted on an outside wall. Looking at pump options instead, there are pumps which only would start once per day and there are also pumps that can be fitted remotely, away from the indoor units.
But the starting point is to ensure that the pumps you got is fitted in accordance with manual and best practices. (Anti-vibration, foam, pads can also help)

Thank you so much that is really helpful and appreciated. If I get fobbed off by the installer who says.... "it's supposed to be like that" what do you advise I do? Is there anyone trusted and recommended in the South London area who could review for a second opinion?