Aircondition will not run and the digital thermostat is blank. Unit was running all day.

Quote:

---

Originally Posted by claud1

aircondition will not run and the digital thermostat is blank. unit was running all day.

---

Check battery and 24 volt transformer .

A blank thermostat indicates a loss of low voltage which originates in your indoor unit. The simplest of reasons would be a blown low voltage fuse or a tripped low voltage circuit breaker.
It could also be that a safety device has tripped, like a float switch... check to see that your unit is draining properly. Is your unit in the attic? Check for a float switch in the pan under it. Is it in the basement? Check for a condensate pump with a float in it.
Also check for a float switch on the condensate drain where it exits the indoor unit.
If any of these are tripped, it could indicate that the drain is clogged.