Thanks for the response tuffluckdriller.  I like your username.  We are on Vancouver Island on the West Coast of Canada.  We are known for our moderate temp.  with at most, a couple of weeks a year below zero.  We very rarely get significantly below freezing.  The unit was very quiet all spring, summer, and it gradually got noisier through fall and now in our coldest part of winter, I have realized that something has happened once again.  A 60Hz buzz resonating into our living room from the outdoor unit which is down one floor and on our concrete patio deck.  The fact that this concrete patio is poured right up to the foundation makes me see how this resonating could be happening.  Still, I was told prior to the install agreement that these things are amazingly whisper quiet.

If you read some of my other posts, in this thread you may get more info to help with your curiosity.  Appreciate your interest.  Thanks.

geo fan, interesting about the 12 SEER.  I didn't know that, but yesterday I did stumble on the net into a page talking about the R22 refridgerant being banned.  This will apparently cause need for me to replace my condenser??  Have you heard that?

Back to the topic at hand.  Not 24/7.  And it occurs in both modes of operation.  My thermostat on the wall will click, followed by the furnace fan coming up, and simultaneously the compressor starts up and my lights dim briefly while this starts.  I have wondered if the draw from the heat pump dropping the line voltage like it is could be causing something.  When the compressor is up and running the voltage is also back to normal.  All told the dimming takes place for about 1 second.  At times I will see a bunch of steam rising from the unit indicating to me that it is effectively defrosting.  After a defrost cycle, the coils are frost free, and there is a small block of ice around the compressor inside the unit at bottom.  I expect this is normal?

The buzzing could be caused by a contactor.  I would expect it to sound a bit more clackity, thoughts? This is a definite deep 60hz vibration that is capable of travelling through about anything.  We must turn up our television to hear it.

engineer, thank you.

1).If this was the case, should the unit become quiet after some operating time?

2.)The unit does not ice up in summer.  It cools our large home effectively and condenses a lot of moisture inside the house unit which is then pumped out.

3.)Not sure of the status of charging, these guys have played with that in the past, evidently.

4.)I really like the idea of an outside opinion on my entire installation.  I was unsure of the ramifications on my warranty.  I suppose I should read the warranty paper a bit closer.  I have no faith in the original installer any longer.  They have been succesful in getting my warranty replacements through Maytag though.  I wouldn't want to put this at risk.  This guys is the only Maytag rep in the area.  Does this matter?  Can I call up a different supplier and still have the good warranty respected?

Internet trouble shooting always is a challange, but hey, I'll add my thoughts as well.  The compressor has rubber mount that will become stiffer as the temp outside drops.  This isn't normally a problem, but I believe in your installation you have mentioned the concrete slab it is setting on and this could very well allow the noise to transfer through to the home.  You might want to suggest to the installer to place the unit on an isolation pad to see if this reduces the noise. 

Regards,

I will definitely try that.  Any suggestions for make/model?  I do have an hvac supplier in Victoria that is quite high volume.  I will endeavour to get one. 

Thanks Eric.