Why does my air conditioner still stay on??

Question

Ive had my ac looked at, cleaned, recharged and changed the thermosat, its a 100x cooler then it was but now when its on it clicks on at 80 and stays on... and it says 71 on the thermosat... its a brand new one so it shouldnt be that... why doesnt it shut off??

its a small apartment so it shouldnt take that long to cool off and never had problems before i called them out...

its a old school thermosat with mercury in it.. not a digital one..

Answer 1

The thermostat is probably not level or is just off by  several degrees.

Or it may not be wired correctly.Keep an eye on it so you can get them back over there before 5:00Pm.If you need to.

Answer 2

Thermostat may need to calibrated or there may be a short circut on the thermostat sub base.

Answer 3

The heat anticapator has nothing to do with the cooling that is fixed. Most of the time the walls will breathe warm air on the back of the thermostat and you need to seal the holes where the wires come thru the wall. Plug off the cover and turn on the thermostat and put your face close to the t-stat and see if you feel warm air blowing out.

Answer 4

The mercury type thermostats must be level to operate properly.  Aside from that if it is old there might be a lot of lint or other stuff that can affect it accuracy.  These can also be calibrated using a special wrench.  With a new system you may want to consider a digital.

Answer 5

Most of the other answers are good places to start. One more thing to look for is the anticipater setting. If the service person that installed it didn't know to level the thermostat, he may not even know what it is. If that is the case, I would call a different service provider.