Any help would be great.... I'm a new home owner, and don't know much about this stuff.

I have a townhome that has a blower in the attic (Lenox) and an air conditioner (heat pump) out side. It is all controlled by one of those digital units on the wall (RiteTemp). The blower in the attic does work, and so does the air conditioning unit. I know this because the blower will operate if you manually throw the switch on the wall for the override "on" (however the indicator light does not come on like it used to). The air conditioner also is pumping cold fluid, tested by grabbing the cold pipes that run to my attic.

http://www.ritetemp-thermostats.com/8022.html

Here is the problem. As soon as you throw the switch to run the air conditioner, the blower cuts out, and does not come back on.

Just to trouble shoot the problem further, i turned the heat on and then blower tripped out on this setting also. Again,,, when you manually switch to the fan on position, it does activate the fan w/o the compressor on, but the fan on indicator does not come on. Think i have a bad controller?

Does this sound like a relay or capacitor?

If anyone is local that can give me a hand,,, there is a free Rotella oil change in it for you!!! :)

Thanks guys!!

It sounds like your thermostat has blown the fan relay/switch.
It the override ON switch you are talking about on the thermostat? or on the Lennox unit?
if it's the thermostat, was there a delay before when the unit would start and then the fan would come on?
To check the thermostat, start the unit to cool, and check if there is a signal on the "G" output of the thermostat, which is the fan relay. It seems your cooling power probably comes in on RC, then when cooling is needed it sends the signal to Y the compressor and G the fan.
If it's the thermostat don't fret they are about $40

Without further testing I would guess that the thermostat has gone bad since it does it in heat and cool mode. Get a Honeywell thermostat, the wiring will be the same, I've had bad luck with every other brand out there. Make note of which wires go to which terminals, don't go by the colors as some contractors use different colors to screw with the next guy.

It's possible it could be the circuit board inside the blower, but since you say the fan runs on manual I'm guessing that the auto contacts in the thermostat have crapped out. Some cheaper thermostats have a plate hat screws to the wall and the wires go to that plate, then the thermostat snaps to that plate. Many times the contacts between the plate and stat get corroded or loose and they start doing wierd things. If your's is like that clean and tighten the contacts and try again.

Thats alot for the input guys...i appreciate it!!! :)

This is my first time into this type of equipment, so i'm learning it as we go. This is what i tried last night to determine if the problem is at the thermostat or elsewhere.

I took the faceplate off of the thermostat to reveal all of those pin outs, or contact. I used a wire and jumped the RC to the Y (cooling) and also jumped the RC to the fan relay. I got exactly the same condition,,,, the fan cut out when the compressor kicked in.

Does this mean that the problem is not the thermostat?

Does the fan come back on or stay off after the compressor kicks in? If it stays off it sounds like it's the circuit board. Take the covers off the blower (turn electric off) and check the ciruit board(s) for loose connections, corrosion, etc.

Look for a United Refrigeration store in your area for parts, They are a Lennox dealer.

you say you're a new homeowner, do you have a home warranty?

sorry cant help on the diagnosis.

Hope he's not stuck in the attic