I'm trying to control my heat pump from an arduino. The heat pump external control section is cryptic at best, it has 3 dry contact points X Y and Z , with the following instructions.
A three-wire external controller (with an "OFF" position). The user adjusts the temperature at the heat pump. The user can select pool or spa mode or turn off the heat pump using the external controller.
Connect the external controller wires as follows: l Connect "High" wire to "X". l Connect "Common" wire to "Y". l Connect "Low" wire to "Z".
What would this mean? Treat as a relay in Arduino , digitalWrite(High or Low)? Also doesn't say if 5v DC or other? Thoughts?