What do I do if my vapor line connection on my Lennox A/C has ice forming around it?

Ice forming on the suction line is a sign that not enough heat is reaching the evaporator coil. The most likely cause of this is a dirty filter which restricts the amount of air able to travel across the coil. The refrigerant in the coil is "boiling" from liquid to vapor at a temperature of 40 degrees F when the air returning to it is 75 F and 50 to 55% relative humidity. If the air is not able to get to the coil the refrigerant in the evaporator will not receive enough heat to boil correctly and the temperature of the gas being drawn back to the compressor may well be below the freezing point of water, thus moisture in the air will freeze on it. Check the filter first. Then make sure there is nothing else restricting the air flow back to the indoor unit. If your indoor blower is belt driven, the belt may be loose and need tightening.