Day & Night Plus90
Model: 3893X14473
S/N: CD5AXA042000AAAA
This is a single unit for heating and cooling.

Problem/Symtoms:
1) Heater is not running properly.
2) If it starts it frequently shuts off before it reaches the set temperature.
3) In many cases I can hear the unit running but there is no air movement.
4) In some cases it does not start.

I replace the programmable thermostat and it made no difference.

Suggestions on where to start?

Thank you in advance!

John

You have a variety of problems. Check for the number of blinks on the lite on the circuit board. Then look on the back side of the blower door for the legend and post the numbr of blinks and what the legend says they are supposed to be.