Performed diagnostic on 2012 Lennox system. Homeowner states that system is not cooling. Indoor unit is kicking on and blowing air, outdoor unit is not kicking on. Cycled system for cooling. Checked outdoor unit electrical and system components. System is recieving 24 volt command, but primary motor control is not engaging. Found that high pressure switch was triggered, which was not allowing voltage to pass through to kick system on. Condenser coil is completely clogged, which explains why high pressure switch was tripped. Pulled off all condenser panels as well as condenser fan motor and thoroughly washed out condenser coil inside and out. Reset high pressure switch. Primary motor control engaged and system kicked on normally. Amp draws for compressor and condenser fan motor are within range. Secondary motor control is within range. Refrigerant pressures are now good and system is producing proper temperature split. Filter that is inside unit is the incorrect size, advised homeowner