Checked Heat Pump system. System turns on properly. Checked pressures. 541psi hi side, 109psi lo side. The chart inside the unit calls for the system to be running at approximately 325psi hi/ 93psi lo at 40* outside temp. The system is overcharged. Recovered 1 lb 13 oz R-410a from the system. Replace the air filter, 18x20x1. The system is operating properly at this time. With the higher pressure, the compressor was operating at a higher temperature and could have shut off on thermal overload. With the compressor off, the thermostat has to drop several degrees before the heat strip turns on.