Loud Rining: Indoor Unit or Split AC

[harry.finn]

Hi

I had two system installed today.

Once of them has a very lound "ringing" noise. It is simular to sound you get in copper hot water pipe, it is very high pitched.

It appears to be coming from the indoor unit.

It happens a few seconds after the compresor kicks in outside and cold air is released into the indoor unit.

I am going to get the installer to check it out, but wanted to get an opion from you guys as well.

Any ideas on what could be going on here?

[Brian_UK]

Sounds like the noise is being generated by the refrigerant passing through a restriction of some sort.

If could be a designed restriction, although the noise is not designed, or an unintentional restriction due to a trapped or over-bent pipe.

Is the noise there all of the time the unit is running or just on start up?

[harry.finn]

It is not a contstant noise.

It happens after the compressor kicks in. Both at startup and when the room needs additional cooling.

Once the room is cooled the noise goes away until the next cycle.

I left it on "fan only" last night and there was no noise all night.

A good way to explain the noise is simular to hitting a "tuning fork" if you know what I mean.

[sudarmanto]

I found quite a similar problem last month on a Split AC. The problem is indoor fan bearings damaged, but this damage is not too serious. I can only heard this noise when my ear close to the fans. But when compressor kicks in, then the noise from fan became louder. Compressor from this unit is very shaky and makes outdoor also shaking. This shaking spreaded to the indoor through copper pipes and makes indoor unit also shaking. This shaking makes that damaged fans noise louder and entire room (10 x 20)m able to hear it. All back to normal after i changed indoor fan

[harry.finn]

Thanks for the info sudarmanto.

Should be easy enough to isolate the fan and test this.

It does sound very simular....

[harry.finn]

It was a kink in the pipe.

The installer smoothed it out a bit and the noise in much less noticable.

He is going to replace the pipe next week.

Thanks for your help guys.

[Brian_UK]

Thanks for the update Harry, good to know that it is a problem that can and will be resolved.

[jsimon]

It sounds like the reversing valve my not be fully shifting across
does it make the same noise on cooling and heating