2 Controllers with Munro Smart Pump Relays. Does it work? Yes / No?

[DLane]

@AngryIrrigationMan - which model of the Munro Smart Pump relay is being used? The reason I ask is in a prior post it was noted there is a lower power drawn Munro model that did work. See →

Rachio 3 Pump Start Function

I installed the Munro MPSR242W22, which is the low power pump start relay and had a scheduled run work without the Zone Fault Error! I think the Munro MPSR24 relay commonly in use for irrigation systems using 220v pumps requires more amperage (360mA) than the Rachio 3 will deliver (300mA). The low power relay has a component built into it that lowers its power demand to function to 50mA. It looks like it is working, but the system hasn’t run a full cycle yet of all zones and that will be the rea…

I’d also consider isolating the controllers from each other using a SPDT relay (approximately $7 on Amazon) as was diagramed/discussed in this post →

2nd Gen sharing a pump start relay with a Hunter Controller?

@kcheek - The relay can be by the Rachio. That will be shorter distance with all the wires involved. The distance isn’t a problem, just like a solenoid on a sprinkler valve. While PM’ing with @Gene on this he figured that one Single Pole Double Throw (SPDT) relay would also do the trick instead of two Single Pole Singe Throw (SPST) relays. In this configuration, M (Master Valve/Pump) terminal from the Rachio would need to be connected to NC (Normally Closed) terminal, SC (Sensor Common) term…

If it is truly a current draw issue with the Munro device, then one could use two NO (normally open) SPST (single pole single throw) relays wired in parallel with each relay coil controlled by a different Rachio M terminal. The power from an external power supply (2 Amp +) would go through the Common/pole terminal on the relays with the NO term connected to the Munro pump start signal and the common/return from the Munro back to the external power supply.

So while I don’t work for Rachio, here are the answers to the three questions.

1. I believe so with a low power draw version as mentioned in earlier in this post.

2. I doubt it as I would think this would be a rare case for them to spend the time/trouble/effort to test.

3. See the above solution to isolate the controllers from each other, with or without a beefier external power supply.