Heat pump problem (icing up)

[georgec]

My airconditioning system is not cooling....the unit has power, the fan runs and the compressor is operating. Howerver the condenser and coil lines are icing up when the unit is running. I replaced the filter, switched off the unit and let the ice melt, cleaned the coil fins with a garden hose (did not bend or damage the fins during this process), cleaned out any debri and trash from the outside fan. I turned the system back on and no cool air was coming from the vents (infact almost no air atr all was comong from the vent even though the fan was running. The condenser began to ice up again within 20 or 30 minutes. I am at a loss...what action should I take now?

[HayZee518]

call a hvac tech. the freon is leaking out somewhere. might be the reversing valve. users are not authorized to recharge their system unless you are epa rated and have a valid certificate for freon recovery.

[LazyPup]

I found this post a bit confusing. Technically speaking, in a straight cool Air Conditioner the indoor coil that is in your furnace plenum is properly called the "Evaporator Coil" and the outdoor coil that is in the compressor enclosure is called the "Condenser Coil".

By convention they are often called the same in a heat pump, although when a heat pump is in the heat mode, the function of the coils is reversed.

Whenever an evaporator coil is icing it is indicating a restricted airflow over that coil.

The most common cause of a restricted air flow are;
1. A dirty Filter, however the post states the filter has been changed.
2. Furniture or personal possessions blocking the return air grille.


Although the following problems will also cause a restricted air flow, as Hayzee has already pointed out, they would require the services of a trained HVAC technician to diagnose and service.

1.Dirty evaporator coil - requires some disassembly of the indoor unit and the coils are cleaned with a foaming chemical coil cleaning solution.

2.Low refrigerant level -Federal law requires an EPA certified refrigerant handler to check the level and/or add refrigerant as needed.

3. Defective TEV (Thermostatic Expansion Valve).

4.Defective Reversing valve (generally a reversing valve is only found on a heat pump)

5. Improper fan speed- Some heat pumps use a two speed motor which operates on high speed for AC and a lower speed for Heating. You could have a defective motor relay that has the motor stuck on the wrong speed.

6. Loose or missing sheet metal in the indoor plenum unit.

7 .Improperly adjusted room supply air register dampers. The hand operated dampers in the supply air registers are intended solely to be used to balance the air flow during initial installation and should never be changed by the homeowner.

8. A collapsed duct. This often occurs in the attic space when homeowners stack personal possessions near the ducts and the possessions later fall and collapse a duct.