Hello, everyone. I am keeping fingers and toes crossed that there is someone here who can help me. This is a long, complicated story. I'll try to make it short.

The tech specs: 16-seer Ruud heat pump, variable speed, electric. Four ton unit, 2,300 +/- sq ft home. Tons of insulation, energy star windows, etc. Thermostat - Honeywell, set on 71 all the time. 15 kw heat strips. Installed new in 2008 (last week of 2007, close enough).

The problem: Unit runs normally for a few days, only kicking high-speed fan on (or second stage? in the cycle) when it is below 23+/- degrees outside. Keeps home comfortable. Then, unit apparently starts defrost cycle but will not go into it. Kicks on cold air to run defrost cycle, heat strips do not kick in to compensate, unit tries to complete defrost cycle but does not. There is no whoosh at the end of the cycle, even after several rounds of this. After a few minutes, and after it has cooled the house from 71 to about 69, heat strips kick in. Brings temp up about 1 degree, then repeats attempt to defrost. Lowers temp in house again, but not as much this time. This cycle just repeats over and over and over again. The only way to get it to stop is for me to turn it off at the thermostat, let it sit for about 20-30 minutes at least, and turn it back on.

Part two of the problem - When it is warmer outside, nearing the 50 degree mark, instead of cooling the house more, it heats the house more. So, I end up going from 71 to 69, but then back to 71 and up to as high as 73.5. (I have two thermometers other than the thermostat).

Part three of the problem - If I do the thermostat reboot, sometimes it doesn't work. In order to get it comfortable in my house, I have to set the thermostat to about 80 degrees, let it hit 74 or so, and then cancel out of that to let it resume normal programming. Sometimes it works, and the unit resumes normal functioning when it kicks back on after the temperature falls. Sometimes it doesn't work, and the unit goes straight back into the cool cycle when the temperature reaches 71 and it comes back on.

This has been going on for about 18 months now. Yes, it gets stuck in cool mode in summer, and it gets colder and colder. It used to happen once or twice a month, now it is at least two or three times a week.

What has been done - Three different HVAC companies, two abandoned by me because of incompetence. One of them was out here probably 6-8 times, the second one told me my 15 kw heat strips were 10 kw. Yeah, that's rocket science, making that mistake.

The latest guy seems to be the best, and he's also getting as frustrated as I am. So, repairs that have been made - thermostat replaced, didn't fix it. New guy discovered that the unit was overcharged, removed excess refrigerant. Also, the sensor bulb that controls how much refrigerant the unit calls for was attached with duct tape, and he fixed that. Lastly, the sensor that sends the indoor unit the signal to kick on the heat strips when it goes into defrost was not hooked up properly. We thought that fixed it but no. After that, he tried replacing the defrost board. It worked beautifully for about four days, and then today, after the outdoor temperature changed drastically - about 30 degrees colder - it is doing it again.

I had left this morning to do some errands, and when I came back, it was 68, set on 71, in the house. I called the new guy who wanted me to run outside and take the cover off the unit, see what the code was, since the outdoor unit was not running. By the time I got out there, it was running. I ended up turning the unit off, since I'm supposed to be working right now and don't have time to mess with it, etc., but instead I'm searching the internet for possible solutions.

I'm ready to have a heat pump shooting party here. I've been sick, my husband has been sick. We are either freezing or burning up. We have an oil-filled space heater we use to stay warm in our bedroom at night. My electric bill is through the roof. I am literally at the end of my rope with this thing. If we can't figure it out soon, I'm going to ask the manufacturer to replace it.

Does someone, anyone, have a possible answer?????? Please!