When you go to replace your heat pump, you will want to pay close attention to the actual heat pump wiring when removing the old unit. As with any type of electric changes, you will want to make sure the power is off to the unit and that you also turn the actual unit off at the thermostat as well before doing any maintenance or replacements.
The best way to not confuse your heat pump wiring is to make sure you mark the lines as you are removing them from the burnt out unit. You can use wire caps or even different colors of duct tape to mark each of the wires as you remove them from the old unit, you can also write on these with a sharpie marker for better identification later. When you clip the wires, you will want to cut the lines closer to the unit being removed to allow plenty of extra wire to work with during installation.
Your old pump and new pump should be similar in appearance and in many cases there will be etched symbols or markings on the unit where the heat pump wiring comes out of the unit. Mark the wires accordingly and then simply match them on the new unit you want to install.
When you go to reconnect the heat pump wiring be sure to use copper conductors for all supply connectors. Make sure the voltage requirements are met on your replacement part, you can be sure you get the correct replacement by following the specs that apply to your specific model of unit.
Be sure to also check your ampacities and over current protection specifications by reading the rating plate, before reconnecting the heat pump wiring between your component and the blower itself. You should be looking at an exact replacement to the one you are taking out of the furnace or air handler. If they do not appear to look the same, you may want to question that you may not have the correct replacement for your model.
You can also find a heat pump wiring diagram for your specific model to help you along, by checking the manufacturers website and help forums in relation to the make and model of your unit. When installing the new part you should be able to then easily match up the wire connections with the wires you marked when you took out the old component.
Replacement Part Types
Some heat pump wiring is simply couplings that screw onto the new component, where as others have the wires actually running into the power unit itself. Depending on the method in which the make and model of your machine was made and on the age of machine in question. On older units the systems were not yet designed for easy maintenance and repair, and in this case a lot of the internal wiring will be hard wired into the components. You may have to do some improvising to make your replacement work on an older unit, the main concern being that the unit will bolt securely into place and that all wires match up as needed.