Heat Pump Blues

Snafu

I am hope someone can assist me in determining what the issue is with my heat pump heating.  22 year old Heat pump (&air Conditioning): Concept 1000 3ton with electric emergency heat, Armstrong air handler with a White-Rogers 1f58-72 thermostat. This is my first experience with heat pumps. I have been in this home for 6 months and the unit ran flawlessly during the cooling season. During the fall and early winter I had no problems keeping the home at a steady 71*. When winter recently settled in here in TN I began to understand how heat pumps operate and their limitations. I learned that calling for more than a 2 degrees increase in temp kicks in the electric emergency element which this system does do. When the temperatures got fairly low for this area (20*)  A couple times I had the blower turn on only to blow cold air. The only way I could stop the blower was to turn the thermostat way down. In a few minutes I could hear the compressor kick on and the heat pump blow 80* air. This past week was pretty cold for us with lows of 11* to 15*. Twice this week I woke up to the blower blowing cold air and the outside coils were pretty Icey.  After researching and watching a few YouTubes I learned H. Pumps will freeze up  and go into a defrost mode. I also learned that during this period the emergency heat should be activated.  The past three nights I placed a thermometer that records the high and low on a register over night. Each morning the low was 45* with a high of 114*.  I guess this tells me two things. 1) 114* says the emergency element does work  2) the element is not being told to kick on at the proper temperature.  Am I on track here ?  Now - how to resolve this ? Is it possible this is in the thermostat ?  or more than likely a sensor or control board in Air handler ?   The white-rogers thermostat has a aux and a emergency light on the side.  These do illuminate if I manually place the thermostat slider into the Emergency mode.  They do not illuminate when I ask for 3* of extra heat which does seem to start the electric element.   I am sure I will have to call a technician at some point but at 22 years old (R22sys) I don't need to place a lot of cash into it.   Have any ideas for me -    many thanks in advance. 

Ironman

The auxiliary heat is energized by the defrost control in the outdoor unit during defrost, not by the thermostat.

You mentioned ice on the outdoor coils. Is it ice or frost? If it’s ice, then the system is probably low on refrigerant. If it’s frost, then the unit may not be defrosting properly. This assumes that you’re keeping the area around the base of the unit clear of snow, ice, and debris.

The unit should also be installed on “pump ups”, not set directly on the pad.

Snafu

Thank you - I would say frost not solid ice. Base is pretty clear - there may have been an inch or so of blown snow at the bottom edge. To confirm - I can manually turn on Aux heat at thermostat. Something is turning on Aux heat but not until about a temp of 45* I have not witnessed it going in defrost as it's always in the middle of night. I assume it works.

Ironman

It sounds like there’s an issue with your defrost control.

Snafu

Thx a bunch.