Just moved into a new house with two heat pumps. I expected there to be two breakers for each heat pump, for a total of 4. However there are 5. Any ideas what each of them go to?
The 5 breakers are labeled:
10kW Furnace
15kW Furnace
A/C
A/C
15kW Furnace
Without more information I can only speculate. The units labelled A/C are probably your outdoor units. Whether they are actual heat-pumps (reversible for A/C and heat) I don’t know.
With these types of systems there is usually an Air-Handler (AHU) that has the blower and evaporator (reversible to be a condenser if it’s a heat pump). That they are labelled “Furnace” is probably because they contain electric heating elements. This is common in a central heat-pump system.
Why you would have 3 air-handlers and two outdoor units remains a mystery as they are usually one-one, but It’s possible one doesn’t have A/C. You should be able to identify the three AHUs as they would need to be accessible to clean/change filters etc. Examine each one. The connection to the outdoor unit is usually pretty obvious as it requires two insulated pipes running to the outdoor unit, one quite a bit fatter than the other.
The model numbers on the outdoor units can be used to determine if they are bi-directional “heat-pump” or uni-directional (A/C only).
Thanks for the advice! I’ll crawl under the house and check it out further. I tried turning on the fan only of one system then the AC, then turning on the fan only of the second system then the AC. It appears that the blower is furnace_15kw_1 for the first unit (_1 being the breaker number) and the blower is furnace_10kw_10 for the second unit. The compressor must be ac_9 for the second unit, and I don’t have a clamp that caught the compressor for the first unit. I do have a clamp on all of the necessary breakers, but the current must be going from the leg I’m not hooked to to neutral because I didn’t measure it. I guess it is possible the compressor runs on 120V, but seems strange.
Anyway, I’ll keep investigating.
I have a 5ton heat pump and it has three breakers. One for the outside unit and two for the air handler and electric backup. My house has an in-law addition with it’s own smaller heat pump. It has two breakers, one for the outside unit and one for the inside air handler/electric backup. Size does matter… 
Yeah, I believe that is exactly how my house is hooked up too. I was getting really confused because the CT that I thought was hooked to the outside unit breaker was actually connected to the clothes dryer. Makes a lot more sense now what is going on.
Thanks for the help!
