Air Conditioning - Mini Split Squeel

I just completed an install of a Freidrick 18000 btu mini split heat pump. Everything is ok except for an iritating high pitched squeel when in the cooling mode. This unit was installed in a computer control room and must be eliminated or the system must go. I have installed other mini split's and have encountered the same problem, only it was not in such a sensitive area. Can anyone help? Thanks

All these units are the same model?? have you contacted the dealer who installed this and get taken cared of underwarranity?

Since this was just put in, I'd contact the installing dealer to have the come back. If they can't do anything, then have them contact the company to see if they have had any issues with the noise.

Unfortunatly I am the instaling contractor. This is the fourth unit I have installrd in this same application, one was a Sony two were Samsung and this last one was Freidrich. All have whistled, I have e-mailed freidrich Tech support and am waiting for a reply. Problem is these units are not very common in the states yet and good advice is hard to find, even from the tech suport guy's, and I don't speak Chinese or Japanese, and thats where they all originate from. I have a feeling the source may be the metering device, some I have talked to say they use cap tube, I think it must be exp. valve. All tech data I can Find dosent help.

Hi Doc.

My applolgy.. I didn't know you were the installing dealer.

Does the noise happen in heat mode or just cooling?

I only put one of these unit in about 13 years ago, and it was a/c only.

Think it is the reversing valve not up to par??

It's a heat pump, and the noise only happens when running in the cooling mode. This is the 5th or 6th one I have instaled from varying manufacturers and they have all had a squelling problem to diffrent degrees. From all of the info. that comes with these units and all the research I have done so far I can not determin what type of compressor or metering devices are used in these types of units. There is only one service port on these things so I can only get one pressure reading high press. in heating mode or low press in cooling mode.I have started a relationship with the tech support guy from Freidrich but all I have found out so far is that he knows less than I do about these things "we dont sell many of those for use here in the states" is one of his more curious statement's.
And the unit Keeps on squeeling........