Low Flow Shutoff for RO

[wmick]

For the pressure switch setup, you should really want a start stop circuit of some sort.... This will prevent it from starting and stopping as the pressure flutters...
Sorry for the crude diagram..
You need a relay or contactor that is rated for the amperage of your motor, and has 2 or 3 NO (normally open) contacts.
One normally open pushbutton and one normally closed pushbutton.

You will need to hold the start button long enough for the pressure switch to close.
The auxillary NO contact from your relay will be closed.... so you can take your finger off the button...

If the pressure switch or the Stop button break the circuit, the coil will de-energize, all the contacts open... and you will need to press start again.

The 2 contacts and "M" on the second rung are your motor... You can get away with just one of those contacts if you need to...
startstop.JPG

[wmick]

How about a float cutoff switch for the feed tank? I can't find a link at the moment but I think something simple like this could be good for people like me with a simple one-pump RO (just got it and am setting it up for the first time). 110 power cord for the RO pump plugs directly into the float cutoff switch. Anybody using one of these they can recommend?

This would work good... any of the sump pump type would work... Still might need a relay or contactor, if the float switch is not rated to take the motor amps, itself.

[Ghs57]

That's another good idea. But once again my problem would be when I switch tanks. I'm ROing the truck tank into the main holding tank, then concentrating the holding tank (which is also fed by on-site maples), then going to do a wash with the wash tank. A shutoff on the unit solves the problem.