Hey, I’m just getting into home automation using Home Assistant. My first project is to make my water system a bit smarter.
I have a rural property where a water tank is filled by a bore pump. There’s a float switch in the tank which turns power on and off to the bore pump. There’s also an irrigation controller at the bore pump location which turns on daily. Essentially, if the water in the tank drops, the bore pump switches on to fill it.
I’d like to control what times of day the pump switches on, or trigger it with other inputs in the system such as solar power generation level. I’d like to add some weather smarts into the solenoid too. I purchased one of these from alibaba, which I’m assuming can switch the solenoid on/off with a 24v line, and the bore pump on/off with the 240v line. What I’m wondering is how to integrate the bore pump switch into HA so I have a “tank full/not full” message if the circuit is open/closed. I guess I could include it in the bore pump switch, but that wouldn’t provide any message to HA about the tank status.
Hi Tamsy, thanks for your suggestion. I already have a tank level switch (a float in the tank), I’d like to use the existing switch state to control the pump.
ie: tank switch is on = activate power to pump.
Sorry if this seems quite basic, I’m just getting started.
Thanks that diagram helps. So the float relay switches a low current to the Shelly Uni, then the Uni sends the state to HA which decides on whether to send a low voltage to the pump/solenoid relays.
(apologies again for the simple question, I’m really just getting started)
With the float switch, you want to trigger the relay coil. I’m guessing your float switch will be closed going open so drive either the relay negative or positive of the coil through the float switch.
Other side of the relay NC or NO (test) will go directly to the Shelly uni input, take it low to GND
Like you see, there is huge inrush current every time you start the pump. And it’s going to eventually weld relay contacts together.
You should look for contactor instead of relay. Something that is rated for inductive load.
If you “need” to go with alibaba relay, look for the 30A model.
If I’m not mistaken, it’s underpowered for the inrush current. AC-3 (single-phase) rating of CA7-9-10: 13A–15A. So unless I added an inrush limiter or soft starter, a contactor with a 15A–20A AC-3 single-phase rating would be better. Does this make sense?
Yes it makes.
I’m not pro of this field, but I expect that contactor rated for motors x amps / watts is for nominal power and counts that there is higher peak.
