These tend to be mains powered with an internal float switch to engage the pump.
A separate float switch provides a volt-free contact to cause the demand for cooling to be interrupted in the event the pump fails.
I can monitor the "safety" switch and implement a similar interface to the plant -- including *commanding* the AC off, if it is currently calling for cooling (otherwise, a smart system may signal a cooling failure).
I don't want to modify the actual pump appliances (they are varied). But, if I *assume* they all are effectively just power-gated pumps, I think I can monitor the internal float switch by sensing when the pump calls for power. (If I could monitor that float switch directly, I would just turn around and power up the pump).
How safe to just put the coil of a relay in series with the pump's power (mains) and use that to indicate the state of the pump?
Any ideas as to how I could *force* the pump on in cases where there is NOT enough condensate to trip the float switch?