Found heat pump going off on high-pressure at 600 psi. Generally this happens because not enough air movement is going across indoor coil. Plugged a 3 inch hole that was around the line set to try to get more air through the coil. Plugged the floor, where the copper comes through the floor. Checked The blades on the indoor blower wheel. They they are clean. Check both sides of the evaporator coil. They are clean. Check the bottom of the evaporator coil to make sure it was having good contact with the metal it sits on. Led sped the blower up too high. None of these things made any difference. I believe the ductwork on your house can’t handle the amount of air that is required for a 4 ton unit. This would make the coil overheat, which would cause the pressure on the high side to go up and cycle the outdoor unit off on high pressure. I recommend you call the people that installed this and let them deal with this. If it was installed less than a year ago, state law requires parts and lab