I have a york heating and airconditioning split system with two separate thermostats the one for the larger unit is lMODEL #1F78
5/2 DAY PRGM
MV TO 30V.50/60Hz.OR DC
1.5 AMP. MAX
BATTERY REPLACEMENT
2 AAA ENERGIZER

I do not have the manual and do not know how to actually program it. Would like it to stay at 72 degrees all the time on the cooling system. How do I program it? It keeps going off at different times after we get it going because it isn't programmed corectly

I moved your question so it will be more easily viewed.

None of the information you provided actually told us who made the thermostat. Without that we can't tell you where to go find the instruction book.