Just wondering if I can hear peoples opinion on this.

I had a 7kw Panasonic split installed over a run of 11 or 12 metres.

After the install, the tech came back to add extra refrigerant due to the run being over 10 mtrs.

It was fine before, although with a slight hissing sound (which is why the tech thought the refrigerant may have been a little low).

Now (with the extra gas) I find that the indoor evaporator unit makes this constant noise, and it's quite noticeable.

Particularly when the compressor ramps down and just idles low.

It used to only do this on start up for a very short while, but now, it just does it constantly.

The closest thing I can tell you it sounds like is when a steam iron releases steam.

I made a basic recording to help identify the sound right next to the evaporator.

I can also hear it in the pipes just outside the unit, and it's ever so quiet (but more of a hissing sound) near the condenser outside.

I'm wondering if it could be possibly overcharged or something, as this is not a normal operating noise.

Would appreciate any help or feedback/advice.

https://docs.google.com/file/d/0By_0...p=docslist_apihttps://docs.google.com/file/d/0By_0...p=docslist_api