The unit is a Tempstar DC 90 Ultra High Efficiency. For the last couple of weeks it hasn't been performing well, we turn it off, then a day or so later turn it on, and it seems to work fine. Today, it is attempting to "blow" but it sounds like it keeps starting/stopping and no cold air is coming out. I can move the setting on the wall to "on" or "auto" and there is no change in the output.

Curious as to what is wrong - it's supposed to be over 90 degrees here today, so I would appreciate any thoughts asap. Thank you very much.

Check the blower motor. I could be shutting off do to internal overload. It also could be a bat start capicator. Both are located in the inside unit. Look at the capacitor. It will be a small silve canister looking componet. With 2 brown wires on it coming from fan. Is the top of it distorted? Try spinning the fan while it's tryingto start. Does it continue to run now? Feel the motor It should be warm but not so hot you can't hold on to it.

How old is your system? You may have warranty left. (Parts and labor) With the info you gave sounds like you may have a variable speed blower. If you turn the Fan switch to on at the thermostat will it blow air or do you hear it kick back and forth trying to start?