What is needed for a low pressure switch?

[diesels77]

Hello all,
I have a Deer Run 125 hobby RO. Currently it is gravity fed. I am adding a shallow well pump for a feed pump for next year. I want to add a low pressure switch (cutout) so when I run out of sap the RO will automatically shut down so I don't ruin the pressure pump. It's 220v, I just don't know what all parts or relays to get. Any advise?
Thank you,
Scott

[Tweegs]

One of these might work for you:
http://www.dwyer-inst.com/Product/Pressure/SinglePressure/Switches/
But to get it to operate the way you want, you may need to add a momentary bypass switch to get the motor started.
Look at the specs, watch the videos, they’ll explain much.

If I’m not mistaken though, a regular pressure switch may react to a sudden loss of pressure. At least I’ve got that rolling around the ole noggin…no time at this moment to confirm.

[Father & Son]

Get ahold of Ray and have him tell you what you need or better yet have him send you what you need.

[diesels77]

Get ahold of Ray and have him tell you what you need or better yet have him send you what you need.
Thank you! That's what I'll do. I didn't even think of that.