I have a Lennox Central Air Unit from 1989 that began to give me
problems last week.

First last week the copper line on the furnace/central air unit stated
to freeze. The unit subsequently shut down. When I tried to re-start
the Central Air at the thermostat the blower fan would not turn on.
After a period of time (a few hours) I was able to turn the AC back
on. I don't know why the Central Air unit wouldn't turn back on?
Possible Freeze Stat?

I suspected the refrigerant charge was low and had a tech install 5lbs
of R-22 and check for leaks. No leaks were found.

Now I have the opposite problem. I no longer have a freezing problem
now the copper line, furnace and basement ducting is dripping from
condensation. Last night the Central Air Unit began to make a loud
grinding noise. I couldn't tell if the blower fan was making the
noise. Like before the unit would not come back on until a few hours
later. Flood-back?

The condensate pump is coming on but I suspect come kind of flow
problem from the drain pipe? Maybe the unit was overcharged?

Any suggestions?

Joe E.