I have been reading up on my AC/heat pumps and still have some questions. From what I understand a Heat pump is typically always an AC unit in the warm months. But is an AC (split system) always also a heat pump, or can you just have a split system AC unit. What is the best way to distinguish between the two? Is there a way to tell on the data plate? I don’t see a lot of AC/heat pumps where Im from but when I do I really want to know what Im looking at.
An air conditioner is a heat pump. It removes unwanted heat from the living area and ejects it outside.
What is commonly referred to a heat pump also has the ability to remove heat from the outdoors and release it to the living space. This is accomplished through a reversing valve (and a few other components) that reverses the function of the indoor and outdoor coils. In an air conditioner, the indoor coil is the evaporator and absorbs heat that is rejected from the outdoor coil, which functions as the condenser.
So when reversed, the indoor coil becomes the condenser, and the outdoor coil is the evaporator.
Both AC and heat pumps are produced in split and package versions.
There are a few extra components in a heat pump, but they are not always easy to spot: 1. Reversing valve, 2. Defrost control (required when in heat mode, as the coils can freeze up), 3. there is almost always back up electric strip heat in the air handler - heat pumps aren’t able to extract enough heat much below freezing, 4. the thermostat usually has a system setting for “emergency heat”, which will disable the compressor and heat with only backup heat.
Hard to explain everything in a MB post - just ask if you want more info.
Here’s a couple of diagrams that help to explain:
Look in the condenser for the reversing valve.
There is a circuit board inside the electrical panel for defrost control, but none in an A/C. There are Emergency Heat Settings on the thermostat, none on an A/C.
There is an accumulator, not in an A/C.
There is another “large” circuit breaker for resistance heat in a HP, not in an A/C unless it it electric heat, then none of the other stuff is there either…