trader_4 wrote in
:

On Monday, June 8, 2015 at 12:07:34 PM UTC-4, Boris wrote:
Thought I'd start a new thread.

I spent about five hours yesterday taking apart and cleaning the a/c
condenser. It didn't help.

When I arrived on scene, the a/c was working fine. Cold air was
blowing out of the vents. The refrigerant drier cannister happens to
be located on the small line outside the evaporator. This line was
very slightly warm to the touch. The larger copper line going into
the evaporator was cold to the touch. The outside of the plenum was
also cold (not freezing).

After about 30 minutes, the a/c unit's fan turned off, the furnace
fan remained on, and the evaporator line outside the plenum, and the
plenum, got warmer.

Time to clean the condenser. I turned off the thermostat, pilled the
40 amp fuse at the a/c unit, and disassembled the side panels, the
fan, and any wiring as necessary. The compressor had an orange vinyl
insulated sort of pull down 'hat' over it. I took that off, too, to
get the compressor specs, if needed, and I put my hand on top of the
compressor. It was hot enough that I couldn't keep my hand on it for
more than a second or so, but not hot enough to cause immediate
burns.

There were lots of leaves in the drip pan, but not much came out of
the condenser. I first vacuumed both sides of the entire consenser,
and there was not much debris at all. I then wetted and sprayed foam
on the outside, and rinsed from both the outside and inside, until
all runoff water was clear. Actually, I was surprised at how little
dust/dirt there was. The only thing that was really dirty was the
temp sensing unit that sits on the small copper line, right where it
enters the compressor. I removed it and cleaned it off good.

I got it put back together, turned it on. The outside temp was now
100 degrees. The indoor temp was 77, and I called for 66 at the
thermostat. Cool air started coming out, measured at 64 degrees (I
guess the attic ductwork was really hot) and it ran fine for about 40
minutes. Then, warm air came out. The a/c fan stopped. I hand
checked hand temps at the plenum, and it was warming up again.

Crap.

I'm calling another company out for a another look before I replace
anyting major.

I would look at a wiring diagram for the unit and see what
it takes for the condenser fan to stop running. IDK how they
are wired, but my first thought would be that the thermal
protection for the compressor would stop just the compressor,
not the fan too. If that's true, then something else is
wrong, eg bad contactor, that is stopping both the compressor
and the fan......

I did find all the specs and wiring diagrams inside the unit when I took
it apart.

The schematic will help someone more knowledgeable than I.

When I'm inside the house and I notice the vent air no longer cool,
that's when I look outside and see that the a/c fan is not running. So,
I don't know if the compressor got hot and turned off itself and fan, or
the fan turned off, and the compressor then got hot and turned off.
Yesterday, there was one time when as soon as the vent air got warm, I
ran to the a/c unit, and the fan was still on, but then within a few
minutes, stopped.