AC/Heater Unit turning on and off, fan still blows...

[destrekor]

Based on the pictures what I am finding strange is that the right side is clogged and the left side is not and that there is a vertical dividing line between the two, the dark band. After cleaning, there is nothing to indicate a delineation between the two sides. Nothing that would lead one to understand why only the right half got clogged.

In the last picture shown is all the shrouding not fully replaced?

Yeah that's interesting.

OP:

I'm curious - is that perfect delineation between two sides on the same face of the unit more of a before/after type thing? Cleaned half of the face and showed you?
Was more than one face of the unit itself completely caked? One picture shows one of the four faces/sides of the cube completely caked, and then the other photo shows just one perfect half of one face caked.

 

[NutBucket]

Is there any reason your unit is on the roof? Around here, they're all at ground-level (Northeast US). Being up there, I can understand why it's so caked with dirt - that's gotta be a pain to clean.

That's pretty common in SoCal (and apparently other parts of CA). Not exactly sure why other than space? Personally I'd rather have it ground level and shaded to make it a bit more efficient.

I did see one house that actually had it about 6ft away from the home. That was almost certainly for noise reasons but I'm sure the additional airflow doesn't hurt.

 

[Hans Gruber]

I have never seen a commerical unit on the roof of a house let alone any home unit on a pitched roof.

 

[thestrangebrew1]

This is an older house and the original unit was on the roof, so that's where they put the replacement. My last home had the unit ground mounted. I'm not sure how bad the other sides were caked, I wasn't up there when the service guy was up there. He just took some pics and sent it to me. It was a before/after type thing though. I'm going to wait a month and go back up there to see how bad it gets though.

 

[Carson Dyle]

So, was that all it was? You're now blissfully chilled?

How did your wife's boss's husband not notice the dirt?

 

[thestrangebrew1]

So, was that all it was? You're now blissfully chilled?

How did your wife's boss's husband not notice the dirt?

Yep. Spent all weekend indoors while it was 100+ outside. It was glorious. I was up there with my wife's boss's husband and didn't notice it either. We just opened the panel up where the electrical and compressor were and looked at it. We didn't open any other panels up, just didn't think dirt would be that bad in it for only being installed 1.5 years.

 

[Carson Dyle]

I live next to a large city park, where up until about five years ago there was a dirt BMX track about 150 yards from my house. In the summer I open all my windows at night to cool the place down, and everything in the house was always coated in a fine brown dust. They moved the BMX track to another park in town and landscaped and planted grass in the area. The difference in dust since then is amazing.

 

[Red Squirrel]

So, was that all it was? You're now blissfully chilled?

How did your wife's boss's husband not notice the dirt?

That's what I wonder too, didn't OP notice all the dust when diagnosing the unit originally? Though to be fair it was on so thick it almost looks like it was just made that way lol.