AC Unit Brain Fart

[infinity]

I'm trying to recall what the function is of the two wire cable that goes from the AC blower unit in the attic to the AC compressor unit outside (not a mini split). Does this control 2-wire cable provide 24 volts to close the relay at the outside unit or is it just for a contact that closes when calling for AC with the 24 volts coming from the outdoor unit?

 

[Tulsa Electrician]

24 volt to relay in conditioner
Edit add pic

 

[Ken_S]

It energizes the ac contactor

 

[LarryFine]

In modern systems, the 24v comes from the air handler, and energizes the compressor contactor.

 

[infinity]

24 volt to relay in conditioner
Edit add pic

It energizes the ac contactor

In modern systems, the 24v comes from the air handler, and energizes the compressor contactor.

That's what I thought thanks! The old stat was removed so I don't know how they had it wired and the unit is over 25 years old so the typical modern circuit boards and color codes don't apply.