Trying to control irrigation pump with ST

Hi all, I currently have a Flotec irrigation shallow well pump that I’d like to control with SmartThings. The pump uses a two pole connection from the box (2 hot wires, no neutral) on a 20 amp circuit, and is configured for 230v. I have seen other posts here on the board, but nothing the fits my situation exactly, so I apologize if this has been posted before and somehow I missed it. I’d like to use some sort of z-wave controller, and have seen another post referencing use of a contactor along with an Aeonlabs z-wave controller, but in that situation it was a 3 pole connection (not 2 pole like mine). I’m not sure if this solution would work for me and if so what parts I could use to get it to work. Any help would be greatly appreciated!
Thank you,
Ken

Something I would worry about first is the reliability of Smart Things…
What happens to your irrigation system if it fails on? What happens if it fails off?
Make sure it is not possible to burn your pump up - or flood your field.
Maybe a no water cutoff on the intake, plus a timer that limits the on cycle.

There are no end of two pole contactors - all cheap. A 24 V coil one is:

You can also get 120 V coil ones in the same price range.

Thank you so much for the reply Robert! If a contactor is the way to go, I don’t know much about them. You gave the link to the 40amp (I guess that would be okay with a 20 amp circuit?) 24V coil one and mentioned 120V coil ones but I don’t know how to match that up with a relay like this one or is there another one that I could use with it?
Aeon Labs DSC26103-ZWUS - Z-Wave In-Wall Micro Controller https://www.amazon.com/dp/B008VWBNAU/ref=cm_sw_r_cp_api_tYsZyb6G7E73R

You make a good point about the pump being stuck on. It’s just for a small yard but would still be a problem if I wasn’t about to turn it off. I’ll need to consider some type of safety mechanism to prevent that from happening.

Thanks,
Ken

You are rapidly leaving the area where I would feel comfortable advising. Maybe some actually knowledgeable people would chime in…
If it were me - I would hook the output from the Z-Wave controller directly to the coil of a 120 Volt primary contactor. I like Contactors because they are special purpose relays used to control motors. The contacts hold up better. The contactor current rating does not matter - as long as it is greater than the motor requires. Motors require more current as they start. You still have to arrange power to the pump; Contactors just close the circuit. I definitely won’t advise on that.
Be careful with the Z-Wave controller. It’s input connectors have trouble handling 12 gauge solid wire. Lots of reviews mention stripping the screws.
Let us know how it goes…

Did you find a solution. I’m trying to do something like that myself.

Could do something like this.

I haven’t actually decided to try this yet, but what I had planned to do
when ready is to use one of the following Z-Wave compatible controllers for
my sprinkler pump:

Intermatic CA3750
GE 12726 or Aeonlabs ZW078-A

I hope this helps!