My compressor unit shuts down before the thermostat is satified. It does cool down the house but in stages not at one time. It runs fine but will not run more than about 10 min straight. Fred

Brand and model of thermostat?

Brand and model of thermostat?

Armstrong SCU10 series by Lennox. Honeywell " Magicstat" model CT2400 Mike

Is this the thermostat you have? If you turn it to fan on instead of automatic does the fan come on and continue to run?

http://customer.honeywell.com/techlit/pdf/69-0000s/69-0789.pdf

My outside unit will go on for a fe minutes and die and the fan kept running... We ended up buying a new outrside unit that was it was not necessary, all we needed was the manual thrermosthat. We bought a $9.99 manual thermostat from Walmar t and try it... It is easy to install just follow the color cables...

Yes this is the one. If the fan control switch is turned to on the fan does run. The only problem is that the high side shuts down too early. The thermostat still isn't satisfied for temp but the unit shuts down. If I'm only cooling one degree at a time you will not notice an early shut off, but if it needs to cool down perhaps three degrees it will shut off after cooling one degree. It's as though the unit is controlled by time not the thermostat. I wounder if an electrical device or pressure sensor is the problem. Heat works perfect . Mike

It could be the thermostat. Eliminate it from the circuit to force the A/C to continue to run uncontroled by the thermostat. If it runs and does not shut off then you will know it is the thermostat.

Post back with your findings on this first test. Then we will go from there.

Brand and model of thermostat?

AprilAir is the brand of thermostat.