My outdoor unit keeps freezing over. Why?
Hi, what is happening is this is a heat-pump split system. When it starts to ice the outdoor coil up, this unit has a defrost board, along with defrost thermostats that are clamped around copper lines with in the condenser unit. Both time and temperature activated. The board is time, while the thermostats are temperature. On the board, you can see 3 intervals, 30, 60, and 90 minutes. This is set by the factory and will have a small wire attached to one of them, maybe the 30 minute, all depends on the unit. If it doesn't go into defrost, and the ice keeps building and building, more then likely the defrost board is your fault. They are a problem on most all heat pumps. When the unit goes into its defrost mode, you will see the condenser fan motor stop, the reversing valve will shift into the cooling mode send hot gas through the outdoor coil to defrost all or most all of the ice. It will stay in this mode until time is up or the thermostat senses the line temp and tells the board to start the heat again. If you don't see this happening at all, you can replace this board on your own if you are able, as they are very easy to change out. Only if it is not going into this mode should you change it. Its normal for ice to form on the unit, but not to stay and not to defrost. If you are having to shut it off or using a hose to remove the ice, replace this board. You will need to get the part number off of the board, all of your thermostat wires also connect to this board, so you can make a drawing on how all is wired and take the board with you, or take all numbers from board and the model and serial number, and name of the outdoor unit with you to a appliance parts house to get one. If you have a Granger's anywhere close to you, this will be your best bet to find it. You have to be a C-20 or C-38 contractor to get one at a heating wholesale house. If this unit does go into defrost, and is heating OK, like I said, ice is a normal thing. There are only 4- screws holding the board in place. Turn off the power at the box near the unit. The board has 4 stand offs where the screws go through to keep it from grounding out to the metal behind it. I hope I have been of help to you. Please rate me on my help. Thank you, and I wish you the best.
A/C, Heating, and Refrigeration Contractor.
Dec 18, 2010 |