Yes, low refrigerant can be a cause of your system not running. A heat pump uses a reverse refrigeration cycle to claim heat from the outdoor air and move it into a home. The refrigerant system usually has protective devices in the electrical circuits that will interrupt operation if certain conditions exist.One of those conditions is low pressure.est Answer: There are a couple of possibilities as to why the unit quit working. All units that required freon, even heat pumps, have pressure switches in them. If the freon is low or none, the Low Pressure switch and will activate, shutting the unit down to prevent comprssor damage.