Vibration on Electrolux mini split

[sayao]

Hi

I have installed a 7000 Btus Electrolux hi-wall mini split with the authorized services with a wall mount. When the compressor is on, it causes vibration on the wall which produces an annoying sound (seems like a ressonance sound). The wall mount has anti-vibration rubbers, but its not containing all the vibration.

What could be causing this? Maybe too much gas (it came with gas for 16 feet but the pipes are more or less 6 feet)? Ubalanced fan?

PS: I have contacted the authorized services, but they said it's normal, but i suspect they are lying or are just dumb.

Thank you.

[Brian_UK]

It could be an unbalanced fan or it might be something touching the casing.

Try and remove the access casing of the outdoor unit; now run the system, quieter or not?

Check the pipes inside the unit, the ones that you can see/touch, are they touching anything? If yes then gently separate them.

[paul_h]

What is the wall made out of?
Shouldn't have a problem with most inverter splits these days, even with no anti-vibration mounts under the outdoor unit.
maybe you are hearing the outdoor unit through a window, maybe the piping in causing the vibration, ie, the outdoor is isolated fine, but the vibration through the pipes carry and the pipes are hard against the wall or ceiling.

[Magoo]

Vibration isolation is a fine art, not acheived with rubber mounts and a wall. You need total separation. Best to mount out door unit on the ground, with rubber mounts.

[sayao]

The wall is made of bricks and cement, about 6 inches of thickness.

The pipes are not the problem, because they are not touching the wall, and the wall is vibrating. The vibration comes from the unit that transfers to the wall mount and is transfered to the wall thru the whole room.
You can feel the wall vibrating if you touch it, but it's not a very serious vibration, however it produces a very annoying sound and dissipates to the other walls.

Mounting the device on the floor is not an option because it's the 4th floor of an apartment.

The support service is coming on the saturday morning, i will tell them to check if the fan is ok, if there is any internal part touching the casing and if the r22 gas calibration is ok.

Thank you for the replies!

[paul_h]

Is it an inverter or fixed speed conventional?
Don't think you've stated or been asked before. If fixed speed conventional, then yes, it's normal for vibration and they should not be mounted on the wall really.
If it's 4 stories up on an apartment, that's a horrible place to put it, service and warranty would cost you heaps.
(members locations are disabled so I have no idea where you are so such installation may be normal there, it's not here in australia)

[sayao]

It's a fixed speed convetional.
I live in Brazil, and it's very common to mount those units on the wall here.

The unit is on the 4th floor, but there is acess to it by two windows, one on each side.

I considered buying a inverter one, but it was more than the double of the price, and i did not know that the convetional one would vibrate.

My next-door neighbor bought the same brand and installed on a similar wall (same material since it's the same building) and it does not vibrate. The only difference is that my unit is 7000 Btus and his is 9000 Btus (his appartment is on the side that gets sun, mine does not).

[paul_h]

Is normal for vibration from a fixed speed unit, never a good idea to fit them to a wall. Install better anti vibration mounts.

[sayao]

Here are some pictures of the unit installed (see attachments).

Thanks.

[croc1774]

Hmm what happend to the washers ?
I would say that because you have shortened the pipe run to (6 feet) you might have problems with noise.
You can get anti vibration mountings for the back plate and washers for the nuts.
What you going to do with that pipe work ?

[monkey spanners]

Where are the rubber washers that go between the brackets and the unit feet? Also as Croc said, where are the metal washers for the fixing bolts in the wall!

[Brian_UK]

Seen the pictures; not surprising that you have noise through the wall.

Compressor has a motor and is bolted to the unit, the unit is bolted directly to the wall; result motor noise travels straight from source to indoor wall.

Anti-vibration mounts required for the joint between the unit and the bracket.

http://aspw.co.uk/index.php?main_page=index&cPath=18_19
file:///C:/Users/Brian/AppData/Local/Temp/moz-screenshot-12.pngfile:///C:/Users/Brian/AppData/Local/Temp/moz-screenshot-13.png

[stufus]

All of the above.
A picture speaks a thousand words.
Must have been a lot of PLO after the install.
Cheers
Stu

[sayao]

The rubber washers are there, but not visible on the photo. They are about half a inch thick.

Maybe it's loose on the wall because it's missing the metal washers, causing the vibration.

I will ask them to put the metal washers and maybe a rubber piece between the wall mount and the wall.

Thank you for all the replies :)

[Magoo]

Some manufacturers fitted shipping straps over compressor, they need to be removed.