David I have same HP in a dual fuel system. I did listen to your video clip. People have different perceptions as to noise. What is offensive to some is not to others and vice versa. While it might be helpful to hear the condenser running at the higher temp for comparison, operationally I don't think you have a problem. If this is a big deal, you can call your installing dealer out to listen to condenser at thelower temp range. I would be surprised if he finds anything mechanically wrong with the unit. IMO

The lineset is the original lineset. It is secure in the attic, but who knows if it secure in the wall. I would think yes, because I cannot move it much in the vertical section, when messing with it in the attic. The lineset set is perfect. I think it is 5/8 and 3/8, which is what the xl15i was spec'd for. I called trane and if necessary, there seems to be a way to get a field rep. I am hoping I won't need it. The problem is the noise is not horrible. But, it is damn annoying and should not be, or they wouldn't sell too many of these things. I am thinking maybe they can move the unit a foot further away from the wall and my unit and put it on isolators.

Our Carrier heat pump is now 10 years old. The outdoor unit was very quiet when first installed, but weather and age lead to rattles. I cut thin strips of rubber to act as bushings/washers to silence the rattles between metal/metal or plastic/metal connections (grill/body panels). Our Silencer system is now silent again. We replaced the indoor air handler at the same time as the outdoor unit. I specifically wanted a quiet fan because our old one was loud. The A/C guy sold me on the single stage, variable speed unit and he also installed a sound deadening baffle where the air handler connects to the old metal duct work. In addition, the unit sits on rubber bushings on the concrete floor. It works well, especially the way it slowly ramps up to speed, and is generally quiet. The only time it will make a loud noise is in the winter if you set your thermostat really low at night and then the metal ducts will pop in the early morning due to the higher thermostat setting coming on. We solved this problem by only dropping the temp 2 degrees at night for better sleeping/economy. Heat pumps tend to work best with small changes in demanded temperature. We also have the electric strip backup, but it rarely comes on. It's been a great system, and I hope it lasts 20 years.

Thanks for that link - very helpful read. So, I'm still trying to wrap my brain around all this before I go to far. Let me explain. First, I'm trying just to understand how this works. I understand it in theory and in that article but, in our setup, it looks like all it is really servicing is the water spigot on the side of the house. The water comes in from the left, down into the tank and also to the right through the honey well then just... on to the water spigot that comes off the house. That's it. Now, I CAN simply unthread the pipe a bit further down, and then into another pipe right by it, to hook the house to the well water in an emergency - as it was shown and explained to me by the seller. So, is it to keep and regulate pressure to the house, its there just in case of that? That might all make sense to me except, why does it make the bang sound when I use water out in the yard from a different spigot. I can't seem to understand how it is even involved there. I see the one pipe go into it. That's it. So anyway, on to what the article says, and others after I've googled a bunch. So, banging on the side of it, it does sorta sound more thud ish than hollow, so I do wonder if it is water logged. I understand if it is water logged the pump will turn on immediately any time you use the water. That is the case here. It does have the air valve at the top, and air does come out - not water. So that is good. I read I need it to be pre charged to the psi (minus 2) of what the pressure needs to be for the pump to turn on. Or two less than the .. in (something). I can't find the exact term again as I type this but it was in-something. SO now what I'm trying to figure out. How do I find out what that number is, I don't see anything on the pump. Am I to put the pressure valve on the drain at the bottom and see what it is? If it's over pressured or under pressured wouldn't that give a bad reading? Is that what the honeywell is for? It says 50psi It looks like on the right. I don't know what the "diff" is on the left. So, should I turn off the pump, drain everything, drain the tank, then pressurize (or depressurize) the air to 48 psi? Everything I see says this is a simple task and I feel like I'm almost there, almost understanding it... just not quite there yet. One thing I do know for sure, it's a good sign water didn't come out of the air inlet. ;)