Noise issue with a Fujitsu split

[Kabeinto]

Hi,

I’ve been reading the forum for a long time and I've learned a lot: thank you! This is my first post.

I’ve just had installed a 3x1 FUJITSU mult-split system: two 3,5Kw units, and one 2,5Kw unit. Split 1 (3,5Kw) is about 70 cm from the compressor, and splits 2 and 3 are about 7 m each one. Vacuum and leak tightness nitrogen tests were completed (in that order).

The thing is that split 1 makes a noise, and I’m not sure if it’s normal. It doesn’t seem to be the typical plastic “chirp”, but instead it’s like a conduit noise or like circulating fluids (gas?). Just one split makes the noise, the one closer to the compressor. On the other hand, it seems to work fine. The noise appears at the beginning, then goes on cyclically, and it can also be perceived at the end, even when the electric current is switched off.

I hope the noise can be heard in the video:

https://www.youtube.com/watch?v=ATnpW4y3UOk

It appears at second 50’’: then the expelled air hides it more or less. When the split is turned off, after minute 3, it keeps on and is still clearly audible. Is it normal? If not, what it could be the reason?

Any advice would be gratefully received.

Thanks!

[Glide]

Hi,

Could it be the short pipe?

Fujitsu reccomends minimum pipe lengths:

https://www.fujitsu-general.com/uk/s...plit/0220.html

What happens if piping is less than the minimum recommended length (3 metres / 5 metres)?

If the product is installed with less pipe work than the minimum requirement specified by Fujitsu engineers, noise and/or vibration issues may occur and also the system may not perform as well as it is designed to. Fujitsu will not cover warranty claims for issues caused by units not being installed in accordance with their manuals.

Check the page 18 of the following manual:

https://www.valleyairconditioning.co...s-brochure.pdf

Could you check the pipe lengths for your unit in the service manual?

best regards!

[Kabeinto]

Hi,

Could it be the short pipe?

Bingo! You are right, Glide. According to the outdoor unit installation manual, at least 5 m are required between the indoor unit and the compressor. I will get the installer back. Thank you very much!

[Glide]

Awesome!
Are you going to put the longer pipe?

[Kabeinto]

Yes, I'm. The idea is looping the additional pipe run behind the outdoor unit. It's hanging on the wall and there seems to be enough room.

[nike123]

Some time ago, when I was instaling split systems, I was dealing with that problem by making simple muffler out of copper pipe of higher diameter and copper end caps fort hat diameter with brazed pipe of reqired liquid line diameter at the midlle!

[Glide]

Yes, I'm. The idea is looping the additional pipe run behind the outdoor unit. It's hanging on the wall and there seems to be enough room.

Did you solve the noise issue?