Upon arrival discovered that system was tripping on a high head pressure and customer said that the cooling side wasn't working Customer had system set to heating and was 78 degrees and ambient temp outside was 63 and discovered that while in heating mode system had tripped the high head pressure due to high demand for heat and outdoor temp being to high Also let customer know that getting more insulation for the attic would help hold temps better so they don't have to run temp high in the house, customer wanted to hold off for now on insulation Left customers house with system operating properly