I have a new 4 ton A/C and gas furnace installed in Jan 2015 by a contractor.
This replaced a Colman 4 ton that I installed myself about 25 years ago. The new
A/C Condensing Unit is a Trane 4 ton 4TTR3018-60. The A/C has been running all
summer with out a problem.
Today, after being off for a couple of hours, it started up and the following
(1) the house lights blinked for about 1/4 to 1/2 second.
(2) the condensing unit ran twice as loud with more vibration as it normally
does for about a couple of minutes and then it resumed its normal
(3) During the time it was running, there was absolutely no cooling. The
temperature at the bonnet was the same as the temperature at the return air duct.
I shut the A/C down by adjusting the thermostat up and called the service tech
who is coming tomorrow morning. After waiting an hour, I dropped the thermostat
and it started right up with no lights blinking. The bonnet is running about
14-16 degrees cooler than the return duct which is normal.
When I read the specs for the compressor, it says the following:
"The Climatuff® compressor features internal over temperature and pressure
protector, total dipped hermetic motor and thermostatically controlled sump
heater. Other features include: roto lock suction and discharge refrigeration
connections, centrifugal oil pump, and low vibration and noise."
Question: Is it possible that the compressor detected a problem and just shut
down but the Condensing Unit fan would still keep running? Also would a 1/4 to
1/2 second blinking of the lights be symptomatic of the problem?
Without being there, I'm not getting any big ideas what
might be wrong. My first thought was dusty condenser, but
that's unlikely on a unit less than a year old.
Be interesting, see what the tech finds. Please follow
up on this list, we can learn from you. Thank you.
I have a Dust Eater filter that was back washed about 10 days ago. In any event,
the Condensing Unit (probably the compressor) had a problem as soon as it
started so I don't think the filter came into play.
Here is what the tech said:
While it is possible that there was a temporary power failure that caused all of
the compressor racket, the more likely problem was a stuck TXV valve in the A
coil as described in the links below.
Starting in 2014, Copeland, who makes the compressor, started
adding a rust inhibitor to the compressor. The inhibitor had the consequence of
occasionally freezing the TXV valve thus preventing any circulation in the
system. When the TXV valve freezes, it causes the compressor to struggle and
finally shut down.
The solution is to add a cleaning fluid of some kind (A/C Re-New ?) to the
system and run it for 48 hours to get rid of the anti rust inhibitor and free up
the TXV valve. If the TXV valve is still frozen, then the TXV valve has to be
The tech said keep an eye on it and if it happens again, they will come out and
flush the system and replace the TXV valve if that is necessary.
Here are some relevant links:
Explanation of Problem
Youtube Video How to Fix. Includes about about 140 comments
Sounds like a tech who keeps up to date a lot more
than I do. Please keep his company number, and
reccomend him to all your friends. Good person to
have on the rolodex.
And, thank you for sharing with us.
Christopher A. Young
learn more about Jesus
What if you lost power for 1/2 second from a squirrel playing on the
line of a train hitting a utility tower? Maybe the noise you heard was
not the condenser fan but the compressor trying to resume operation
against too much pressure. In a couple of minutes, a protection device
shut off the compressor because of heat or pressure.
It seemed like something like that might have happened BUT the noise and
vibration started exactly when the A/C started. The noise I hard was probably
from the compressor trying to start after being off for at least a couple of
hours. I had set the thermostat up a couple of degrees in the morning because it
was a nice day and we opened the doors. In the afternoon, it got hot so I closed
the doors and lowered the thermostat and that's when the lights blinked at the
same time as the compressor tried to start.
I've had my refrigerator compressor overheat and shut off because of a
power interruption, but the interruption occurred after it was running.
I don't know how many amps it take to trip a momentary interrupter on a
power line. Maybe there happened to be an exceptional load on the line
at that instant. Your compressor was enough to trip the power company's
device, and your lights flickered.
In our neighborhood, we have drop down fuses that will disconnect the
transformer if there is a high current problem. Then you have to call the
utility to come out and close the fuse. No momentary interrupters that I know of
unless there is something at the sub-station (2 miles from my house) that does a
This says a fuse must be replaced if it disconnects the circuit. It
says the small circuit breaker on a distribution lines is a recloser.
When a pecan limb fell onto bare distribution wires behind my house,
lights in the neighborhood blinked. I imagine that was the recloser
across the street. If the limb had kept the lines pressed together, the
lever on the recloser would have popped down and a guy with a long pole
would have had to come to reset it.
I have to call the man with the pole. When I call, I tell that I am out there with my tree trimmer and is it
okay if I do it myself. Of course, they scream at me No! No! and send their own pole guy out IMMEDIATELY!!
On Mon, 24 Aug 2015 17:08:41 -0400, Arnie Goetchius
Does it have a restart lockout timer to prevent the compressor from
short cycling? If not, it may have been liquid slugged and overheated.
Letting it settle for a while got it working again and I hope you
didn't really hurt anything.
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