Greetings All, I have had problems on a couple of occastions with my AC lines are freezing up. Googling around seems to always talk about low refrigerant leading to the coils freezing up, leading to the lines freezing up. This isn't the case. ONLY the lines are frozen, the coil is clean as a whistle. All filters are replaced monthly (son has allergies), and the external fan is turning at normal RPMs. A couple of years ago I had the system service and they did add some refrigeant, but they said it really wasn't that low. Any ideas? Thanks in advance.

Are all registers in the house open? Try increasing indoor fan speed, is there anything blocking the return grill? What we are looking for is lack of air flow across the evaporator coil. Mike

If you lines coming out of the Evaporator coil are frozen over that means the coil itself is also frozen over. Did you take the front off the coil to look at it? There are three main reason for the lines to freeze over. Number one is for the freon to be low, number two if for there to not have enough air going across the coil and the third is for the device that lets the freon into the coil to not be working properly, either it could be partially stopped up or if it is an expansion valve it has lost it charge and it is not opening and closing like it should.