We recently purchased a home with 2 heat pumps...one upstairs and one downstairs. The one downstairs is older. However, the compressor on the downstairs unit was recently replaced by a HVAC contractor. The issue we now have is that the downstairs unit seems to run all of the time....even when outside temperatures are in the middle 40s. I realize the air coming from a heat pump will feel cooler than air coming from a gas furnace. Even in the mid 40s, this unit runs for 15 minutes blowing cool air before calling for auxiliary heat. Once the auxiliary heat comes on, the air gets warm and then shuts off after 5-10 minutes. The technician told me that one of the two pipes coming from the outdoor unit should be warm to hot when the unit is running. When he was here, one of the pipes was really warm. However when I checked yesterday, the temperature of the two pipes is very similar. Does anyone have any ideas as to what could be the problem? I would like to get some ideas before I call the technician back and pay another service charge. Thank you.