So this past week my central ac has not been able to cool my home during the heat of the day. It works fine at night, but when its 95 during the day, it just won't cool. I have a little experience in replacing ac parts, but far from an expert. I have a 98 lennox, which used to be connected to a heat pump, but has recently been changed to a furnace type system. So I have the orange wire that goes to the thermostat to change the reversing valve and I have that piggybacked off the yellow wire. During the middle of the day, the compressor will only run periodically. I was checking things yesterday with the voltmeter, and all of the thermostat wiring to the outside unit is getting the power except for the white wire since that is for heat. I have felt the larger pipe, and sometimes it is cool, not really cold, and sometimes its warm. The fan on the outside unit will run constantly, and the rest of the system will run constantly, except for the compressor. Any ideas?

So I know the large insulated pipe should be cold but how cold? Mine is barely cold and wet and the small one I hear should be hot but isn't really warm or even hot. The problem I am having is that my AC unit just can't keep the house cool. It is blowing out semi-cold air and is a year old unit.