My central A/C started acting up today. The thermostat is set at 75
degrees, yet the room temperature remains constant at 80 degrees. The
air circulating fan in the basement is running and putting out a
minimal amount of cold air, but the main RUUD heat pump/
airconditioning unit outside is just sitting there, not turning on. I
checked the circuit breakers and none has tripped.

I would appreciate some pointers on where to look for possible causes
before I call the repairman.

Thanks.

wrote:

My central A/C started acting up today. The thermostat is set at 75
degrees, yet the room temperature remains constant at 80 degrees. The
air circulating fan in the basement is running and putting out a
minimal amount of cold air, but the main RUUD heat pump/
airconditioning unit outside is just sitting there, not turning on. I
checked the circuit breakers and none has tripped.

I would appreciate some pointers on where to look for possible causes
before I call the repairman.

Thanks.

There is likely another breaker at the unit, and perhaps another one
integral to the compressor.

And there's likely a control board and motor relay which can fail or
go into protect mode. Some have status indicators.

Rodents sometimes chew through wires.

--
The e-mail address in our reply-to line is reversed in an attempt to
minimize spam. Our true address is of the form .

Check the high pressure cutout-- it is a little red button close to
where the lines come into the outside unit. Larry

wrote:
My central A/C started acting up today. The thermostat is set at 75
degrees, yet the room temperature remains constant at 80 degrees. The
air circulating fan in the basement is running and putting out a
minimal amount of cold air, but the main RUUD heat pump/
airconditioning unit outside is just sitting there, not turning on. I
checked the circuit breakers and none has tripped.

I would appreciate some pointers on where to look for possible causes
before I call the repairman.

Thanks.

One of the most common problems is the "contactor" which is another name
for a solenoid type relay. It's the final switch (inside the compressor
unit/box) that "clunks" in to connect the 240v to the compressor.
These go bad after 8-10 years and won't close....in principle, much like
the solenoid switch on a car starter motor.