Ashton Crusher wrote in
:

That doesn't sound like all that hot a temperature for teh compressor
to me. But I'm just guessing. I know I've had compressors in the
past that would run all day long and be so hot that you couldn't touch
them without getting burned but they never stopped running. So maybe
it's overheat protection is a little too touchy.

I also got the impression from my AC guy that part of having a proper
amount of refrigerant in the system is so that there is a certain
amount of COLD refrigerant that for whatever reason trickles into the
compressor to keep it from getting too hot. I got the impression that
a low charge meant there wasn't enough of the "left over cold
refrigerant" to cool down the compressor and that could make the
compressor run hot. Sooooo... if there is any truth to that I would
hypothesize that if you were to have your AC guy shove some additional
"freon" into your system, whether he thinks it needs it or not, that
it might make the compressor run cooler and solve your problem.


On Tue, 2 Jun 2015 16:24:50 +0000 (UTC), Boris
wrote:

On 5/5/2015 I sent out a note about my air conditioner not cooling
after being on for a long period of time. I had to drive up to the
Sacramento area yesterday and meet an a/c tech during the late
afternoon, when it got hot (but only 80 degrees outdoors), to
demonstrate what was going on. He figured it out. I had kept
outdoor/indoor/thermostat/vent temperatures for four days running, and
noticed a pattern...cold air blew for a while, but after an hour or
so, no matter the outside/indoor temperature, or thermostat setting,
74 degree air began to blow.

Whe the a/c first goes on, it blows 58 degree air and begins to cool
the house. (I hung a digital thermometer on the overhead vent.) If
the house isn't too hot, it gets cooled down properly and the a/c
turns itself off. If the house is hot, the a/c begins to blow 58
degree air, but after a while (maybe an hour or so), the fan continues
to blow, since the thermostat is still calling to cool more, but the
compressor turns off. All the while, I thought the compressor was
still going, because air was blowing out of the vent, but the air was
74 degrees.

Yesterday, I turned the a/c on at 2 pm, and the house began to cool
with 58 degree air coming from the vent. The tech arrived at 3:15 pm,
and just at that time, I showed him that the vent air was now blowing
at 74 degrees. He went outside to the a/c unit, and noticed that
although air was blowing out the indoor vent, the compressor was not
running as noticed by the fact that the fan on top of the unit was not
running. He measured all the amp/volts at the two main capacitors
(start and run capacitors) and all was fine. He measured the freon,
and it was up to capacity. He then measured the temperature of the
compressor, and it was HOT, at 149 degrees. He called back to his
company and also to the American Standard, the a/c manufacturer, for
advice/trouble shooting. All were baffled.

He then took the garden hose and ran water over the compressor cooling
fins, and the compressor started right up and the vent air went from
74 to 71 degrees in a minute, and continued to decline. He surmised
that the compressor was overheating and was shutting down, as it
should. But, no one knows why the compressor gets so hot. The
outdoor temperature was only 80 degrees yesterday. Even if the
outdoor temperature is 75 degrees, the compressor gets hot after
running for a while and shuts itself off.

The a/c unit is an 18 year-old American Standard model 7A2042A100A1,
R22, used to cool a 1700 sq. ft. single story home in the Sacramento
area. This is my dad's house, who passed away in late 2013.
Beginning in 2012, he used to call me up to figure out why the house
didn't cool properly. We had techs out, and they replaced this and
that, but still no luck. I replaced two thermostats, thinking that
may be the issue, but still no luck.

A month ago, when the tech thought the problem was with the a/c fan,
because it was VERY noisy, he replaced the fan and capacitor for about
$500. But, warm air still blew.

So far, the tech can only explain this by saying that the unit is old,
and just doens't run as efficiently. While I can buy this, I don't
know why this would be. Anyone?

At any rate, to replace the compressor is about $2500, which I could
do, as it seems everything else is running fine, and especially since
I've just replace the fan/capacitor. To replace the entire unit is
about $4500, but they suggest that if I replace the entire unit, I
should also replace the perfectly running furnace, since a new a/c
unit uses the newer 'freon', and they like to match that with the
furnace. I don't understand this. But, to replace both a/c and
furnace is about $10,000. The a/c unit is about a 3.5 ton unit. I
prefer to get by with the $2500 compressor, as I don't know how long
I'll keep the house.

Any thoughts?

TIA


Yes, the tech did say that freon also cools the compressor. He checked
it, and said it was fine. But...I had to ask him to check it. This
company, SierraPacific (Rancho Cordova, CA), is the company that
installed solar pool heat on my dad's roof 30 years ago. It's been
maintained and keeps the pool between 84 and 90 in the summer. I've got
an annual maintenance contract with them. With the a/c, my dad never had
a contract, and would just call any old company when service was needed.
I did add to the solar contract, an HVAC maintenance contract last month,
and they have been very responsive when I call them out. The last two
visits were about 2 hours each doing diagnostics, with no charge. They
come highly rated locally, and on Angie's List (for what it's worth),and
drive around in expensive, well stocked vans. However, they are always
trying to sell something.

I'm thinking I should clean the compressor fins and then see what
happens. If no better, I may call another company out for a second
opinion.

As you can tell, there's a pool at this house. All this reminds me of
last year when I hired a pool guy (I live two hours away in the S.F.
Peninsula) to take care of the pool. The first thing he told me was I
needed a new sand filter. Funny, it always worked well, even though the
zeo-sand was 8 year old on a ten year life span. He wanted $1000 to put
in a new filter. I knew nothing about pool maintenance (I'd rather not
have a pool, but this is Sacramento), but I taught myself, and cleaned up
the filter for about $50. Works great now.

But I digress...