Short cycling occurs when the AC has much more capacity than the heat load of the house. The AC turns on and cools the house very quickly. Quickly could mean 10 - 20 minutes. The short amount of time does not allow the AC to lower the indoor humidity. You feel cool but your are still sweating. It becomes a problem if you live in an area which has high humidity. The 5 ton capacity refers the size of the condenser. The blower in the air handler is adjusted to work with various condenser sizes. Your handler may be able to work with a smaller condenser. I don't have a good feeling about the installation contractor. He has done a poor installation and appears to be avoiding you. What type of warranty does he provide? Make sure you document the problems and stay on top of him.

My GS HP is 15 years old, and the thermostat that was installed with the HP works fine, it just doesn't have any options on how auxiliary heat is brought on-line, i.e., we set back 6 degrees at night. I can't get up in the morning and set the temperature back up 6 degrees or the resistive strips (there are two of them that come on at timed intervals if there is still a gap between the demand temperature and the room temperature). So I was thinking maybe I could find a new thermostat that would give me some control over how the auxiliary heat is handled. For the time being I have just disconnected the resistive elements, so while the system calls for resistive aux heat, it doesn't come on and the HP just continues to run to bring the temperature up. The resistive aux is nice, it does raise the temperature faster, but $$$ ouch.

DavidAndKasie is correct. Heat pumps CAN be set back (turned down) effectively with a setback thermostat that has smart recovery. First, since you say that you don't understand much about how heat pumps work, let's cover that. A heat pump basically is the same as an ordinary airconditioner, with the addition of a reversing valve that changes its functioning to HEAT the indoors instead of cooling. Air conditioners don't so much MAKE cold as they MOVE heat from one place to another. In cooling mode, heat is moved from inside to outside. That's the hot air you feel blowing from the unit outside (the inside blows cool air). In heating mode, the unit picks up heat from outside and moves it IN (the outside unit blows COLD air, the inside WARM). There technically is heat in the air (or an object) down to scientific absolute zero (-459.67F) when molecular motion stops. It's cheaper from an electric energy expenditure point-of-view to MOVE heat than to CREATE heat. Thus heat pumps are cheaper to operate electrically than glowing-red heating elements. However, when the outdoor temperature drops, particularly to the point of ice/frosting, it's harder for the heat pump to pick up the heat and move it inside. So all heat pump system have an auxiliary heat source, typically standard electric heating elements, that activate as needed when it can't maintain the desired indoor temperature without help. This is called the "balance point" -- the point at which the heat pump can't move heat in fast enough from outside to counteract the heat loss that's occurring through doors, windows, walls, etc. Every system and house is different in that respect. The indoor temp drops below the setpoint (thermostat set on 70°F, room temp is 68°F for example), and a 2nd pair of contacts trigger in the thermostat which turns on the heating elements. Electronic thermostats may also do this based on time. If the system can't reach the setpoint (70°F) within a specific time period, or the thermostat senses that the indoor temperature isn't increasing or isn't increasing fast enough, the elements turn on. Of course, the heating elements pull a lot more electricity and aren't as efficient as the heat pump. So the trick after a setback (or having turned the system completely off) is to raise the temperature SLOWLY so the heating elements DON'T turn on. Electronic setback thermostats designed for heat pumps do this automatically. The computer figures out how soon to start the recovery process so it can raise the temp slowly and hit the target at the specified time without using the auxiliary elements (or minimizing use of them). It may take a few cycles for the computer to "learn" the characteristics of a particular system and get the timing right. You can also do it manually, but you have to PAY ATTENTION and not raise the temp too fast or too high at a time. This may take a couple hours at lower outdoor temps. Beware also that if the outdoor temp is well below the aforementioned "balance point" the system may NOT be able to recover the desired indoor temp at all without use of the auxiliary heating elements. Another aspect of heat pumps that you should know about is defrosting. As mentioned earlier, the outdoor unit in heating mode is basically cooling the outside. During some conditions, particularly wet/freezing weather, the coils can ice-up, like a food freezer that needs defrosting. Air can't blow through the coils when they're clogged with ice, so like a freezer they must be defrosted. The system does that by switching back to AIR CONDITIONING mode for a few mins so the outside coils get warm and melt the ice. Now remember that when running as an air conditioner, the system blows COLD air inside the house. During defrost, the auxiliary heating elements turn on, NOT for the purpose of melting the ice on the coils outside, but to warm up the cold air that would otherwise be blowing in the house. There's no way to prevent defrost from happening, the system does that automatically as needed. Some people say that if the outdoor temp is so low for an extended period that the system is running continuously, the outdoor unit is repeatedly icing over and defrosting, then it's best to set the thermostat to Emergency Heat, which shuts off the heat pump and runs ONLY the heating elements ... since they're being used a lot anyway during the frequent defrost cycles.

Anything is possible Crystal so yes t-stats often go bad same as other components. You are asking us to solve things that someone couldn't solve while laying hands on it. Adding to the near impossible task,you aren't giving much information for us to go on. Statments like "My ac never froze up" and "copper pipes outside are cold and wet like they should be"are misleading at best,outright inaccurate at worst. I don't have time to win debates and aurguments in order to answer questions for you. Get a different tech to look at it.