Identical units in new neighborhood but my unit is the one freezing up excessively and has shut down completely. HVAC installer says everything is normal but when your heat shuts off until you manually de-ice the unit that does not seem normal to me. Also told me to take a broom and beat the ice off the unit (which he actually came out and did when I was not at home)???? Should I build a cover over the unit or spray blades with de-icer? Is this a warranty issue? Any suggestions much appreciated?