Why is the pipe freezing between my air conditioner and house?
Answers:
It is not normal and you should not be running your A/C if the line is freezing. You are probably low on freon, or you have a dirty filter. Check your filter first... if it is very dirty, then change it and let the system sit and thaw before running it again. If it is not the filter then call a service man to check your system. Running it while it is freezing up can permanently damage your system.
Added note: I don't mean to disagree with freedomhammer's answer below, but icing is ABSOLUTELY one the most common symtoms of being low on freon. In fact, about the only 2 things that cause icing are bad airflow and a low freon charge. I have been a HVAC contractor for 15 years with over 20 years experience. A low charge causes icing because the pressure in the system is running much lower than design, which in turn means the indoor coil is colder than it is suppose to be. If the indoor coil gets much below 30F, then ice will start forming on the coil and on any non-insulated parts of the larger copper line... usually this is outside near the outdoor unit. Eventually the indoor coil will completely freeze like a block of ice and you will not be getting any airflow at all. The usual complaint with this is the customer says they have cool air for a short while, but then the air flow starts to fall off until it eventually stops all together a few hours later. They shut the unit off, but the same thing happens the next day. I see icing problems hundreds of times each year and the majority of the time it is cause by a slow freon leak. But as I said before, check your filter first!
Other answers:
That is the freon flowing through the pipe. It's perfectly normal. Just turn your thermostat down a little and it will "thaw".
That is the freon flowing through the pipe. It's perfectly normal. Just turn your thermostat down a little and it will "thaw".
When the freon freezes in the pipe it is an indication that your freon level is low. Have a service tech recharge the system.
I agree 100 % with tsunami.
A condition like that is called "freeze back" and it indicated a dirty filter. When the filter becomes excessively clogged the airflow is slowed, and the refrigerant never absorbs enough heat from the air passing through the A-coil inside the ductwork, and as a result the cold travels back to the heat exchanger outside. I had run an airconditioning unit for some time without any filter at all and had a layer of dust build up in the coils inside the unit inthe duct and when I opened it up I found a layer of compaced dust that was almost the same consistency as a piece of felt cloth. This blocks most of the airflow and will result in the lines becoming coated with ice outside by the heat exchanger unit. This is not usually an indicator of low refrigerant levels in the unit, it is cause by restricted airflow. I'd be willing to bet that you are not getting much cold air inside and that it might not be blowing as hard as it used to. Have the filter checked immediately; most likely it needs to be replaced.