I find sometimes that my heat pump interior unit is running but the fan on the compressor outside has stopped. It comes back on after a time. When the fan is not running the compressor outside continues to make noise. Is this normal or is there something wrong?

It is normal for that to act that way in defrost cycle. Depending on what type of defrost you have on unit it will check every 30-60 or 90 min. to see it defrost is needed

Thanks, a follow on question. I have water dripping off the roof and freezing on the unit. I have placed a large plastic bucket on top of one side of the compressor. I am concerned with the weight of the bucket as it fills with water. Any other suggestions to keep this from freezing up the blades until I can get the water problem corrected?