Heat pump blowing cold air

[rockipnt]

I have a heat pump that is about 7 years old. Last night it started blowing cool air when set to heat. I turned it off for a few minutes and turned back on, still just blows cold air. What could be the problem?

[Ed Imeduc]

Out side breakers ok is there power to the outside unit??
Doest outdoor unit run at all ? try to run? If tstat is not calling for heat but "on" does indoor fan run? Need more info here and some one can help you. Post back in the same post here.

ED ;)

[rockipnt]

The outside unit does turn on - runs. The fan is running, it's just cold air coming out of the vents.

[scottg]

At the outside unit there are two pipes on is a small copper pipe (liquid line)and the other is a larger copper pipe with black insulation wraped around it (vapor line). The vapor line should be about the same temperature as outside temperature plus 100 degrees and the liquid line should be about the same temperature as the air comming out the vents.
Check that.
If this is not so then you probably need refrigerant added.