Rachio 3 - well pump running continuously

I replaced an old Rainbird controller with a Rachio 3 and somethings not working correctly - when no zone is running my well pump is running continuously (24/7).

I had my local well company check the controller and pump start relay (both Franklin) and everything is fine there, but when he tested the common and master valve wires connected in the Rachio that go to the pump start relay he could see a current continuously flowing when no zones are “on”. I have a single zone on a rainbird controller and that works as expected (no current when the zone isn’t on).

The setting in the controller is set to “well pump”.

Any ideas? Did I wire something wrong?

seems to be wired correctly, when you say you have one zone on a rain-bird controller, what does that mean? do you have a second controller of a different brand, or are you saying it works fine when using another controller?

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Both, I guess.

I have a 17th zone on a controller of a different brand (rainbird) and that controller only sends current to the (same) pump start relay when the zone is started. I have also rewired one of my Rachio zones to that controller and it works correctly there too.

how are they both controlling the same pump? different pump start relays in parallel?

The wiring to the relay goes “through” the rainbird controller. The M and C wires in the Rachio are connected to the M and C terminals in the rain bird, with the rain bird M and C terminals being connected to relay.

This is how it was when there were 2 rain bird controllers in place. (I was not the home owner when these were setup).

I doubt that is supported. Were the old rainbird and the one zone one sharing the same power supply? That would probably be the only safe situation in which M terminals could be joined together, IF the rainbird uses an air gap relay for the M port.

Rachio and RB are definitely using separate power supplies, so connecting the Ms together is definitely a short - if there is any phase shift between the two, you are seeing currents passing through when both turn the M wire on at the same time.

You probably need a second pump start relay that is parallel to the existing one, or at least use diodes when joining the M wires, anodes towards M and cathodes joined together, or the other way around. You need to prevent current flowing from Rachio to RB or the other way around.

Will let others share their opinion here.


I have the same problem. I only have the Rachio 3 12 zone controller. It turns on the pump as soon as I plug in the Rachio transformer. It worked with my Orbit controller, but the Rachio is supplying power to the pump relay all of the time, even when there are no zones active.
I unplugged it over night hoping that it might reset the controller, and hopefully it wouldn’t energize the pump without a zone active, but nothing changed.
I think there is something wrong with the controller.

Hey there,

@ady624 is correct that the current setup with two controller sharing the same PSR or master valve is not support. To share a PSR or master valve between two controllers requires an isolator. There is a support article here.