Maybe bad bearings on the condenser fan. What the heck are, collasping coolant bubbles? lol

I'm thinking that when vaporized coolant is cooled by the fan, and condenses into liquid form. It's like the noise than the small bubbles at the bottom of a pot makes when the water first starts to boil. Having said this, I really don't know if this happens in an AC.

Get a new "technician".

Any brand can make noise.

A techinician is broadly described as someone who may have as little as 1 year to 3 years of experience.

If they send you a 20-30 something old technician / spin the roulette wheel again... this is a skilled trade.

How much skill is in that of someone that may only have 1-3 years of experience?

What might need to happen to solve the noise problem? -- this is likely to also require skill or the noise will probably come back. ( I cover this in the video below)

I service the Katy, Texas area.

I wouldn't judge the expertise of a service technician based on their age or length of time in the trade. Lots of folks who've been in the HVAC trade repeat the same one-year of work experiences for say, 28 years while others with fewer years can have a more broad range of experience and broader expertise.

In many endeavors, people who work alone often develop attitudes akin to ”this is the best way to do this because that’s what I do”. With no co-workers to collarborate with and learn from, development is limited.

No, it's based on things I find that were done wrong leading to the demise of the equipment.

Choices have consequences.

See it's wrong, knowing it was wrong? How do people that don't do this for a living know that?

I've worked on pretty equipment installed by others, yet some how I get called because they can't fix it.

"Oh wow, I need to call my boss because I don't know what your problem is."

~ Something you won't ever hear me say.

But because I talk to my customers how is it do you think I know what is going on? (You won't see this from a forum board most likely.)

There are several reasons that your unit can be making this noise. Could be a cracked fan blade, fan motor bearings, a compressor going bad. There is no way to really tell from the audio what it is doing and nobody will really be able to do this. We will all have to make an assumption based on what it could be. Best option is to have a technician come out and take a look at it. As far as technicians and the age vs. quality. That is a distinction that you can not make. One of the best technicians I have ever met in this industry is a 21 year old. Been in the industry since high school and eats, breaths, and sleeps HVAC tech. His customer service isn't the greatest but he knows his stuff and studies all the time. One of the worst was a technician with 35 years in the industry that was lazy and didn't care anymore and just hacked things up. But his customer service was impeccable. When you look at a company look at the training programs, ask about the training they give there technicians, any good company will be proud to share that information, after all, the cost of that training is built into the charges you pay. Also remember, the lowest priced company is not always the best. You truly get what you pay for.

How about applying power to the fan without the compressor to help isolate the problem? I would think repairing the fan would be comparatively inexpensive IF that were determined to be the cause of the noise.

-- amateur whose fixed simple heat pump problems

Doing something consistently one way when working solo and not knowing there are better choices is inevitable. That’s repetition, not experience.

Thanks all for your comments. I think my next step is to get a better quality recording and then share it with a local HVAC vendor. (Of course they'll want to inspect it to be sure, and to earn money. But still.)

If it comes to this, have any of you any experience with installing a sound-dampening enclosure around the heat exchanger?

The XC16 Specifications list an optional Compressor Sound Cover on page 4.

wdccruise do you have a link to that specification? This is a 4 ton unit, and the doc I found online indicates that soundproofing is built in. Thanks.

"If it comes to this, have any of you any experience with installing a sound-dampening enclosure around the heat exchanger?"

If you are referring to a compressor sound blanket, this will help some if the noise is coming from the compressor. Not sure about putting a sound-deadening enclosure around the condenser(?)

Honestly, I don't know any reputable company that would attempt to diagnose a problem through a recording. Its just not the way to do it right! I think someone will end up paying more for less in the end. A technician needs to look at the unit, plain and simple. If someone does not want to spend the money to fix it right why would they want to spend the money to fix it over and over again. Insulating blankets and sound blocking insulation on the compressor may be more harmful then helpful. It may buffer the noise and overheat the compressor and lead to catastrophic compressor failure. Some systems are designed for this and some are not. This unit is not designed to be used with an insulating compressor cover. See Installation Instructions for this unit

"wdccruise do you have a link to that specification?"

I linked the specs in my comment above.