Over the past couple years we have had some problems with some heat pump systems going off on high pressure or causing condensers to spring leaks. First, as always verify airflow. If airflow is correct, then move on to gathering the model numbers off the coil and the outdoor units. Per, ICP and Goodman all heat pumps must be an AHRI match. This indicates they have been tested together.

The reason why this is happening is that in the heat mode our indoor coil is now our condenser. Biggest problem with this is that the indoor coil in generally a lot smaller in volume than the outdoor section. When we start to meter in to the outdoor unit liquid starts to stack up in the evap, due to the lack of volume, and then start to cause our pressures to rise quickly and force a shutdown.

When we do an install we typically match our indoor units and outdoor units up....so....e.g GSX130301 with a CAPF3030B6. This works fine for AC only but for heat pumps you generally have to use extended capacity coils.. so... CAPF3131B6.  Biggest thing, still, is to get the match up off the AHRI website, that way we are not guessing and using an approved tested system.