The heat pump is going into defrost mode. It is drawing heat from the
house and pumping it into the outside coils to burn off any frost that
may have formed. Some units even go into the resistance heat mode to
make the process work. It is a normal function of a heat pump.

BTW depending on your heat pump model it can run as low as zero
degrees. I had a GE unit for 18 years and it ran OK (although not very
efficient) down to zero.


ftwhd wrote:

I have what I think is a problem...or maybe its normal.
Once in a great while, and this will be when its in the mid-30's so
I'm not
running when its below 28, after the heat pump has kicked on and
brought the
temp in the house up to the set point, the furnace fan continues to
run,
cold air comes out, and the heat pump's compressor seems to still be
running
but the heat pumps external fan isn't on.

Any ideas??