From: blockedofcourse@foo.invalid   
      
   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?   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)