From: blockedofcourse@foo.invalid   
      
   On 11/24/2025 3:13 PM, ehsjr wrote:   
   > On 11/23/2025 11:54 PM, Don Y wrote:   
   >> 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?   
   >   
   > Use a current transformer, not a series relay.   
   > Ed   
      
   I was trying to be cheap and simple.  Make a little plastic   
   box with a plug on one end, outlet on the other and a contact   
   closure that the HVAC tech could wrap his head around.  Nothing   
   potentially exposed to the user/tech by this device.   
      
   Current transformer needs a burden to keep the potentials   
   "safe" if my kit is disconnected (or, not YET connected).   
   I'd have to build that into the "device" to ensure it doesn't   
   present any issues to installers/users.   
      
   I figure most condensate pumps tend to be of similar capacity   
   and, thus, present similar loads (~100W).   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)